Carlos Alcaraz made light of feeling under the weather as he dispatched Andrey Rublev in impressive fashion to revive his ATP Finals hopes on Wednesday.

The Spanish four-times grand slam champion has been suffering with respiratory problems in Turin and wore pink nasal tape against Rublev but enjoyed a resounding 6-3, 7-6 (8) victory.

The third seed, attempting to win the title for the first time, looked sharper than during his opening group match, which ended in a straight-sets defeat by Norway’s Casper Ruud.

After sharing the opening six games, Alcaraz broke Rublev’s serve with a scorching forehand winner and reeled off five successive games to seize control of the match.

Rublev, the world No 8 who also lost his opening match, to Alexander Zverev, managed to stay with Alcaraz in the second set and could have earned a couple of break points at 2-2 had he not missed a routine ball after chasing a drop shot.

A high-octane conclusion to the match saw Alcaraz fend off two set points in the tiebreaker before sealing victory. Rublev has now lost six successive matches at the ATP Finals in straight sets since reaching the semi-finals in 2022.

“I did surprise myself,” Alcaraz, who had to abandon a practice session on Tuesday, said on court. “I just tried to focus on my game and what I had to do and not that I wasn’t feeling well. Once you step on court you have to forget that. I felt good from the baseline running and felt I had more options today.”

In the late match in the John Newcombe group, the two-times former champion Alexander Zverev underlined his superb late-season form to beat Ruud 7-6 (3), 6-3 for his second victory of the week.

The world No 2 turned up the heat in the first-set tiebreak, banging down a couple of aces to consolidate a mini-break on the way to taking the opener. Ruud missed just nine first serves all match, but errors at 4-3 down in the second set proved costly as Zverev got the decisive break.

Nothing is yet decided in the group, but Alcaraz is likely to need to beat Zverev in his last group match on Friday to qualify. “We’ve played some very tough battles in grand slams this year, so I’m expecting a tough match,” Zverev said of his match with Alcaraz. “I’m looking forward to it and hopefully it will be fun to watch.”

The opening tie of the Billie Jean King Cup finals between Spain and Poland has been postponed because of a severe weather alert in the Málaga region. Organisers said the decision was made “based on guidance from the relevant authorities to ensure the health and safety of all participants and attendees”.

The match has been moved to Friday, with the tournament now due to start on Thursday with matches between Japan and Romania, and Slovakia and the United States. Twelve teams are in Málaga to compete in the women’s tournament, with the men’s Davis Cup final starting at the same venue the following week.

This article was amended on 14 November 2024. An earlier version incorrectly stated that the US would play Slovenia. They will in fact play Slovakia.