Alexander Zverev continued his strong form at ATP World Tour Masters 1000 events this season, beating Diego Schwartzman 6-4, 6-2 at the Rolex Paris Masters on Thursday.

A winner of three ATP World Tour trophies this season, Zverev has now reached the quarter-finals or better at seven of the nine Masters 1000 events in 2018. The 21-year-old German won 84 per cent of first-serve points (32/38) and saved all four break points he faced to move into the quarter-finals after 81 minutes. With a 54-17 tour-level record this year, Zverev is now just one match win away from equalling his personal best total of 55 victories achieved in 2017.

Schwartzman ends his season with a 33-25 record. Without dropping a set, the 26-year-old Argentine captured his first ATP World Tour 500 title in Rio de Janeiro earlier this year.

Zverev will meet Russia’s Karen Khachanov for a place in the semi-finals. Zverev leads Khachanov 2-0 in their FedEx ATP Head2Head series, which includes a five-set win at Roland Garros this year.

Karen Khachanov ended John Isner’s bid to qualify for the Nitto ATP Finals in dramatic fashion, saving two match points to beat the 33-year-old American 6-4, 6-7(9), 7-6(8). The World No. 18, who held three match points in the second-set tie-break, regrouped well in the decider, dropping just five service points (32/37) to advance after two hours and 28 minutes.

Khachanov now moves into his seventh tour-level quarter-final of the season and second at the ATP World Tour Masters 1000 level. Earlier this season, the 22-year-old reached the Rogers Cup semi-finals, falling in straight sets to eventual champion Rafael Nadal.

Isner was aiming to advance to the quarter-finals in Paris for the fourth straight year and maintain his hopes of making his debut at the Nitto ATP Finals in London. The 2016 runner-up ends his season with a 34-19 tour-level record. Isner lifted two tour-level crowns this season, winning the biggest title of his career at the Miami Open presented by Itaú and his fifth BB&T Atlanta Open trophy.