Tsitsipas faces a stern challenge in top seed Novak Djokovic, who rides a seven-match winning streak into their third FedEx ATP Head2Head meeting. Tsitsipas defeated Djokovic last year in Toronto in their only hard-court meeting, and the Serbian got his revenge this year in the Madrid final.

Following on from Greek sixth seed Stefanos Tsitsipas edged out Canadian Felix-Auger Aliassime in a match between two of the most exciting talents on the men’s tour.

Tsitsipas, who had never beaten his 19-year-old opponent, even on the junior circuit, had to be patient before securing a 7-6 (7-3) 7-6 (7-3) win.

Victory moved Tsitsipas closer to qualifying for the ATP Finals in London next month, while German fifth seed Alexander Zverev – another still hoping to qualify and have the chance to defend his title – also needed two tie-breaks to overcome French veteran Jeremy Chardy 7-6 (15-13) 7-6 (7-3).

If Stefanos upsets Djokovic, he will become the sixth player to qualify for the season finale, which will be held at The O2 from 10-17 November. But the 20-year-old can also qualify if Italian Fabio Fognini beats Cincinnati titlist Daniil Medvedev earlier in the day.

Both players carry a lot of momentum into the clash, with Djokovic fresh off the Rakuten Japan Open Tennis Championships title he won last week and Tsitsipas has earned five Top 30 wins in the past week and a half, after earning only five of them between the start of Rome in May and the beginning of last week’s ATP 500 event in Beijing.