Spanish star Carlos Alcaraz, aged 18, on Monday became the youngest player to enter the top 10 of the ATP world rankings since his compatriot Rafael Nadal did so at the same age in 2005.
Alcaraz climbed two places to ninth in the world due to his straight-sets victory over Pablo Carreno Busta in the Barcelona Open final on Sunday. Britain's Cameron Norrie drops out of the top 10 to number 11.
It was the third title of the season for Alcaraz, having won the Miami Masters at the beginning of the month and the Rio tournament in February.
Carreno Busta swaps places with another Spaniard Roberto Bautista Agut, the former climbing to 18 and the latter moving down one spot to 19th.
Novak Djokovic still sits atop the standings despite losing to Russian Andrey Rublev in the final of the Belgrade Open. World number two Daniil Medvedev is out with a hernia problem.
ATP TOP 20
(Players representing Russia and Belarus are banned from competing under the name or flag of Russia or Belarus until further notice).
1. Novak Djokovic (SRB) 8 400 pts
2. Daniil Medvedev 8 080
3. Alexander Zverev (GER) 7 465
4. Rafael Nadal (ESP) 6 435
5. Stefanos Tsitsipas (GRE) 5 770
6. Matteo Berrettini (ITA) 4 570
7. Casper Ruud (NOR) 4 110
8. Andrey Rublev 4 025
9. Carlos Alcaraz (ESP) 3 827 (+2)
10. Felix Auger-Aliassime (CAN) 3 625 (-1)
11. Cameron Norrie (GBR) 3 440 (-1)
12. Jannik Sinner (ITA) 3 029
13. Taylor Fritz (USA) 3 010
14. Hubert Hurkacz (POL) 3 008
15. Diego Schwartzman (ARG) 2 805
16. Denis Shapovalov (CAN) 2 671
17. Reilly Opelka (USA) 2 475
18. Pablo Carreno Busta (ESP) 2 135 (+1)
19. Roberto Bautista Agut (ESP) 2 015 (-1)
20. Nikoloz Basilashvili (GEO) 1 788