Carlos Alcaraz overcame his recent illness to keep his hopes of progressing at the ATP Finals alive with a straight-sets triumph over Andrey Rublev on Tuesday.

Alcaraz had complained about feeling unwell in his defeat to Casper Ruud, but returned to winning ways with a 6-3 7-6 (10-8) victory in 96 minutes against his Russian opponent.

The Spaniard, sporting a pink nasal strip to aid his breathing, exchanged blows with Rublev early on but was able to take control of the encounter after the fifth game.

Alcaraz reeled off four consecutive games from 3-2 down to seal the opening set, closing in on a second consecutive win against Rublev at the year-end tournament in Turin.

The enthralling affair continued to produce some sensational tennis, most notably when Alcaraz brilliantly turned defence into attack during a long rally in the third game.

The four-time grand slam champion later kept his cool in the second-set tie-break, saving two set points before closing out the win to kickstart his campaign.

Alcaraz now sits at the top of the John Newcombe Group ahead of Alexander Zverev's meeting with Ruud later on Tuesday, with the German up next for the world number three.

Data Debrief: Winning the best medicine

After a rocky start to his ATP Finals campaign, Alcaraz's latest showing confirmed that, despite not feeling at his best, he can still pose a threat at the tournament.

The Spaniard struck 31 winners compared to Rublev's 14, but did match his opponent for unforced errors during the contest (20 each).

But it was another victory on a favoured surface for the world number three. Since the ATP rankings were first published in 1973, Alcaraz (21 years and 192 days) is the second-youngest player to claim 20 top-10 wins on hard courts, older only than Lleyton Hewitt.