Of all the sports in the world, tennis may have the strangest range of ages. Tennis players that are considered prodigies may begin their pro career at 13 or 14. By the time they hit 30 though, tennis players may be considered to be reaching the end of their careers.
The game is never stronger than when it features exciting young players barely in their teens and older established veterans who are still effective players. This list includes the best players who are either 21 years of age and younger of 35 years of age and older.
Alexei Popyrin - 19 Years Old
19-year-old Alexei Popyrin might be the best young player hailing from Australia. He had a very successful Juniors career that he capped by winning the 2017 Junior French Open.
Popyrin made some noise this year at his hometown Grand Slam, The Australian Open, where he reached the 3rd round, falling to Laslo Djere. The youngster has also qualified for his country's Davis Cup team. He made his debut for the team in February of 2019.
Malek Jaziri - 35 Years Old
Like some of the other older players on this list, Jaziri has reached much of his success in the latter years of his career. The Tunisian moved up to 42nd in the world rankings in January of 2019.
Jaziri was able to reach the finals of the Istanbul Open in 2018, but dropped the match to Taro Daniel. His career has also featured controversial incidents in 2013 and 2015 when he was ordered by his government to not play against Israeli players.
Zachary Svajda - 16 Years Old
Zachary Svajda, from Pacific Beach in San Diego, California is the youngest professional tennis player based in the United States. The teen, who is a home-schooled High School Sophomore has been coached by his Father Tom for his entire career.
Svajda made waves by defeating Joao Lucas Reis Da Silva, an established tour pro, in the first round of the Claremont Classic in California. The teen, who currently only stands at 5-8, has a bright future in tennis ahead of him.
Kwon Oh-Hee - 41 Years Old
Like Roberto Menendez, South Korean player Kwon Oh-Hee has also continued his career into his 40's. Oh-Hee has spent much of his career playing in tournaments all over Asia. He earned his best year-end ranking in 2005 when he finished 342nd in the World.
The South Korean has won a number of singles titles including events that took place in Indonesia, South Korea, and Japan. He also has a record of 3 wins against 1 loss in Davis Cup play.
Jannick Sinner - 17 Years Old
Jannick Sinner, who was born in Innichen, Italy is currently the top-ranked professional tennis player under 18 years of age. Since he turned pro in 2018, the Italian has quickly risen up the ranks and currently stands at the 209th ranked player in the World.
Sinner has gotten to that ranking by winning tournaments in the Italian towns of Trento, Pula, and Santa Cristina Valgardena. The baby-faced player should continue to be a huge factor in the years to come.
Ivo Karlovic - 40 Years Old
Ivo Karlovic, born in Zagreb, Croatia in 1979, may be one of the oldest players on the tour but he is still a force to be reckoned with. Known for his incredibly hard serve, Karlovic is one of only four players with over 10,000 aces.
The Croatian rode that 156 mph serve to quality showings in all 4 Grand Slam tournaments. He also won Laurels Tennis Academy as a member of Croatia's 2005 Davis Cup championship team.
Andu Mukhtar - 14 Years Old
Mukhtar Andu from Great Britain holds the distinction of being the very youngest player on the ATP Tour. As his career is just getting started, Andu is currently ranked as the 1,575th ranked player on the World Tour.
It is likely that he will get much better and fast. Andu recently achieved his first tour victory with a 6-4 victory over Paul Emmanuel. His eventual success will be dictated by his ability to get his booming serve within the lines.
Luca Nardi - 15 Years Old
Luca Nardi is a baby faced, right-handed player who hails from Pesaro, Italy. He successfully navigated the World Junior Tennis system and quickly moved himself up to the professional ranks. He was able to achieve his first tour win at the age of 14.
Despite his current world ranking of 1,490 Nardi is considered a terrific prospect who is expected to move up fast. The Italian prodigy has a record of 2-1 on the tour with his two wins coming over much more advanced players.
Feliciano Lopez - 37 Years Old
Born in Toledo, Spain in 1981 Felciano Lopez is the first player on this list with a Grand Slam title to his name. In addition to that 2016 French Open doubles win, he also made the quarterfinals of the US Open and Wimbledon.
Along with partner Marc Lopez, he is still a threat to win any doubles tournament that comes around. When he's not playing tennis, Feliciano also works as a model, appearing in campaigns for Hugo Boss and Elle.
Felix Aujer-Aliassime - 18 Years Old
While Felix Aujer-Aliassime will not turn 19 until early August, he has already accomplished much in his young career. The Canadian youngster was very successful on the Juniors tour, winning the 2016 Junior US Open and reaching the finals of the 2016 Junior French Open.
He has now moved onto playing the professional levels of the Grand Slams. He had his best result at this year's Wimbledon reaching the 3rd round and is currently ranked 21st in the World.
Taylor Harry Fritz - 21 Years Old
Taylor Harry Fritz, who is currently the 31st ranked player in the World is also the top United States-born male 21 years old or younger. He has very strong bloodlines, as his Mother, Kathy, was once ranked in the World's top 10.
Fritz won his first ATP tour title recently, winning the 2019 Eastbourne International, defeating fellow American Sam Querrey. He also had a great showing in this year's Australian Open making it to the 3rd round where he lost to Roger Federer.
Roberto Menendez - 43 Years Old
On the complete other side of the spectrum is Roberto Menendez, who at 43, is the oldest player currently on the world tour. The Spaniard born in 1976 turned professional in 2000. His highest career ranking came in 2003 when he was the 341st ranked player in the World.
He is a well-experienced player who has a career record over .500 at 224-201. Menendez has also played a healthy amount of doubles tennis over that time span.
Paolo Lorenzi - 37 Years Old
Despite being one of the older players on the tour at 37 years old, Lorenzi has achieved much of his success after reaching his 30's. His best year was 2017, as he made the 4th round of the US Open and finished the year ranked 33rd.
The Italian-born player won his first ATP Title in 2016 when he defeated Nikoloz Basilashvili to capture the 2016 Austrian Open. Lorenzi finished 2018 still in the top 100, ranking in at 94.
Stefanos Tsitsipas - 20 Years Old
Not only is Stefanos Tsitsipas the highest ranked player in the world under 21, but he is also ranked in the top 10 at number 6. He has already challenged the world's best players falling to Novak Djokovic during the 2019 Madrid Open and Rafael Nadal at the 2018 Canadian Open.
His success has continued this year as he had his best Grand Slam result, reaching the Semifinals of the Australian Open. The sky is the limit for the young Greek player.
Andreas Seppi - 35 Years Old
Andreas Seppi has been a very long tenured player, turning pro all the way back in 2001. Since then he has had a productive and workmanlike career, that saw him win 3 ATP tournaments and reach a career-high ranking of 33.
Seppi has had good showings during Grand Slam tournaments, especially the Australian Open, where he's reached the 4th round on four different occasions. Seppi has also represented his country in the Summer Olympics in three different years.
Philipp Kohlschreiber - 35 Years Old
18-year-old pro Philipp Kohlschreiber has had a long and fruitful career. The German-born player has won a total of 8 singles ATP tournaments to go along with 7 doubles crowns.
Kohlschreiber had his best career Grand Slam showing during the 2012 edition of Wimbledon where he made the quarterfinals. That run boosted his world ranking all the way up to 16th. He has represented Germany in the Davis Cup in the year 2007.
Casper Ruud - 20 Years Old
Casper Ruud is attempting to become one of the most well-known players hailing from the country of Norway. He has an incredibly successful debut winning the first ATP Challenger tournament he ever entered back in 2016.
Ruud began playing in professional Grand Slams in 2018. During the 2019 French Open, he made it to the 3rd round where he fell to the legendary Roger Federer. Rudd is also a fixture on Norway's Davis Cup team.
Denis Shapovalov - 20 Years Old
Denis Shapovalov was born in Tel Aviv in 1999, but his family moved to Canada before he had turned 1-years-old. His Mother was a star tennis player who was a member of Israel's National Team.
Shapovalov has been steadily improving his play and had his best Grand Slam showing at the 2019 US Open. The Canadian made it to the 4th round where he lost to Pablo Carreño Busta. He is currently ranked as the 27th player in the World.
Fernando Verdasco - 35 Years Old
Fernando Verdasco has had a tremendous career where he has earned just over $16 million. The Spaniard has taken on the world's best players and holds an impressive career record of 540 and 404.
While he has never won a Grand Slam, he has won 3 Davis Cups as a player for Spain. He has also won 8 ADP singles titles. Verdasco's highest career ranking came in 2009 when he was ranked as the 7th player in the world.
Roger Federer - 37 Years Old
One of the oldest players on the men's tour is also arguably the greatest player of all-time. The Swede has impeccable career credentials, winning 8 Wimbledons, 6 Australian Opens, 5 US Opens, and 1 French Open.
While it at one point seemed like Federer's career was on a downswing, he has come back strong winning 3 Grand Slam titles since 2017. Federer, who has made close to $125 million in his career, is currently the 3rd ranked player in the world.