Basel, October 24: John Isner avoided a significant blow to his hopes of making the ATP Finals at the Vienna Open, while Roger Federer was made to work for a first-round victory at the Swiss Indoors Basel.
American Isner is ninth in the race to London and had to stave off two match points before sealing a 6-7 (1-7) 6-4 7-6 (9-7) victory over Cameron Norrie, meaning he will meet Gael Monfils or compatriot Shaun Johnson in the second round.
Fellow ATP Finals hopefuls Dominic Thiem, Kei Nishikori and Fabio Fognini also came through their opening matches unscathed.
Home favourite Thiem edged Ruben Bemelmans 7-5 7-6 (7-5), while Nishikori required three sets to get past Frances Tiafoe 7-6 (7-3) 5-7 6-2.
Sam Querrey battled past Jo-Wilfried Tsonga and there were also wins for Fernando Verdasco and Lucas Pouille.
Federer's quest for a ninth title in Basel got off to a rocky start as he was taken the distance by Filip Krajinovic.
The 20-time grand slam champion dropped his serve three times in a hard-fought second set but took his second opportunity to serve out a 6-2 4-6 6-4 win.
A 16th straight win in Basel set up a second-round meeting with Jan-Lennard Struff, who beat John Millman 7-6 (7-3) 6-2 – denying Federer the chance to avenge his US Open defeat to Millman last month.
Seventh seed Daniil Medvedev got past Maximilian Marterer 6-3 7-5 and will meet Andreas Seppi after the Italian overcame Taro Daniel 6-0 6-4.
Australian 19-year-old Alexei Popyrin claimed his first ATP Tour win against compatriot Matthew Ebden, while Peter Gojowczyk and Gilles Simon also advanced.