The 2018 ATP season is over and it has been a hugely exciting one. Although all four Majors were shared among the Big 3 (Roger Federer, Rafael Nadal and Novak Djokovic), the tennis world has started showing signs of the beginning of a transition phase.
New challengers are knocking on the door louder than ever, and we get the sense that the year 2019 might give us a new Grand Slam winner - perhaps a young one.
Many young, future stars have left their mark on the big stage this year. Here are seven promising youngsters who performed well in 2018.
7. Alex De Minaur
19-year-old Aussie Alex De Minaur set an example this year for his other countrymen like Nick Kyrgios and Bernard Tomic. He may not be as talented as either of them, but he is as dedicated as his mentor Lleyton Hewitt.
De Minaur's fighting skills on the court and his never-give-up attitude are almost unbelievable. Just like his mentor, he doesn't have too many big weapons in his artillery either. But his conviction is his biggest weapon, and with time he could develop some firepower too.
Ranking at the start of the year: 208
Ranking at the end of the year: 31
Career-best ranking: 31 (November 2018)
Win-loss index in 2018: 28-23
6. Hyeon Chung
South Korea's Hyeon Chung, who turned 22 this year, had a dream run at the Australian Open. He beat Alexander Zverev and Novak Djokovic with his amazing athletic abilities and never-say-die attitude, but unfortunately had to retire from the semifinal against Roger Federer because of an injury.
He later underwent surgery which forced him to stay off the tour for a major part of the year. But that wasn't before he reached his career best ranking of 19 in April of this year.
Ranking at the start of the year: 58
Ranking at the end of the year: 25
Career-best ranking: 19 (April 2018)
Win-loss index in 2018: 29-18
5. Kyle Edmund
Just like Chung, Edmund also sparkled during the Australian Open and reached the semifinal, defeating Grigor Dimitrov in the process.
He won his first ATP title in Antwerp, and became Britain's new hope in the absence of Andy Murray this year.
Ranking at the start of the year: 50
Ranking at the end of the year: 14
Career-best ranking: 14 (October 2018)
Win-loss index in 2018: 36-21
4. Daniil Medvedev
The tall and skinny Russian won three ATP titles this year, including one in Tokyo. With his big serve and aggressive play, he climbed up the rankings steadily through the year.
Medvedev is a potential Top 10 player, without a doubt. He won the Tokyo title despite entering the tournament as a qualifier, and he didn't drop a single set in the main draw.
Ranking at the start of the year: 65
Ranking at the end of the year: 16
Career-best ranking: 16 (November 2018)
Win-loss index in 2018: 43-24
3. Borna Coric
Croatia's Borna Coric had a dream season in 2018. He broke into the Top 20 this year and to top it all he defeated Roger Federer twice - including once on grass.
Coric also had a terrific run in Shanghai, losing only to Djokovic in the final.
But it's not just about his achievements; the Croat's game has improved a lot this year. He is serving well, his forehand has become more penetrating, and he finished the year by helping Croatia win only their second Davis Cup title.
Ranking at the start of the year: 48
Ranking at the end of the year: 12
Career-best ranking: 14 (November 2018)
Win-loss index in 2018: 40-20
2. Karen Khachanov
Khachanov is another Russian who won three ATP titles this year, including the ATP Masters 1000 tournament in Paris.
His performance in all the Grand Slams was decent if not good, and his fabulous match against Rafael Nadal at the US Open was one of the best matches of the year. With his big serve and amazing forehand, he is already in the race to be a future Grand Slam winner.
Ranking at the start of the year: 45
Ranking at the end of the year: 11
Career-best ranking: 11 (November 2018)
Win-loss index in 2018: 46-22
1. Stefanos Tsitsipas
The youngster who impressed the most on the ATP tour in this year is from a country which is not particularly famous for producing tennis players. Greece's Stefanos Tsitsipas just turned 20 in August this year, and people are already seeing him as a future Grand Slam winner.
Tsitsipas reached the final in Barcelona and Toronto this year, and on both occasions lost to Rafael Nadal in the final - but not before he defeated five top 10 players including Dominic Thiem, Alexander Zverev, Kevin Anderson and Novak Djokovic.
He won his first ATP title in Stockholm, and also won the Next Gen Finals in Milan - thus proving his superiority over other young players.
Ranking at the start of the year: 91
Ranking at the end of the year: 15
Career-best ranking: 15 (August 2018)
Win-loss index in 2018: 46-27
Honorable mentions: Denis Shapovalov, Frances Tiafoe, Taylor Fritz and Matteo Berrettini