No.7-ranked Rublev accounted for Nuno Borges of Portugal 6-3 6-2 in Basel on Monday (Tuesday AEDT).
The 16-time ATP Tour champion from Russia is eighth in the race for the top-eight Finals, trying to stay ahead of ninth-placed Alex de Minaur, who is playing in Vienna.
Fifth-seeded Frenchman Ugo Humbert fired 13 aces while battling past local qualifier Jerome Kym 6-4 6-7 (5-7) 7-5. Humbert's second-round opponent will be Belgian lucky loser David Goffin, who had his own struggles to put down Matteo Arnaldi of Italy 6-7 (5-7) 6-3 6-2.
Seventh-seeded Arthur Fils also had trouble with German qualifier Daniel Altmaier, winning 7-6 (7-5) 6-3 after saving two set points in the first set and coming from a break down in the second.
Australia's James Duckworth suffered an 80-minute 7-6 (7-4) 6-3 loss to Giovanni Mpetshi Perricard while compatriot Alexei Popyrin was also beaten in straight sets in Austria's capital.
Popyrin went down 7-6 (7-3) 6-2 to Czech Jakub Mensik.
STOP THAT, JAKUB 😱— ATP Tour (@atptour) Out of nowhere, Mensik produces an absolute 💎@ErsteBankOpen | #ErsteBankOpen pic.twitter.com/Q7t5v0WZfiOctober 21, 2024
Top seed Alexander Zverev stormed to a 6-2 6-2 triumph over local Joel Schwaerzler and Italy's Matteo Berrettini won 7-5 6-4 against Marton Fucsovics of Hungary.
It was Zverev's 60th win of the year, equalling his season best from 2018.
The German was sympathetic for the teenage wildcard, appearing in just his second ATP tour-level match and hometown debut.
"When you come to your home tournament and probably the biggest crowd you have played in front of, as an 18-year-old and you're playing the world No.3, it's not the easiest thing in the world," Zverev said.
"I did that as a 17-year-old in Hamburg ... I know exactly how (Schwaerzler) feels. It's not an easy situation to be in but he's a wonderful player and he's going to have a wonderful career."
De Minaur opens his campaign against world No.40 Jan-Lennard Struff on Wednesday (AEDT).
With AAP.
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