Kei Nishikori kept up his Japan Open-winning form as he cruised through his Shanghai Masters opener on Tuesday just 48 hours after lifting his second Tour title.
The 14th seed, whose victory over Milos Raonic in Tokyo on Sunday was his first tournament win since 2008 in Delray Beach, eased past China's Wu Di 6-2 6-4 in his first-round match in Shanghai.
Argentina's Juan Monaco was surprisingly brushed aside by Spaniard Fernando Verdasco in their second round tie.
The seventh seed is in the running to qualify for the end-of-season ATP World Finals next month but was out of sorts on Tuesday as Verdasco coasted to a 6-4 6-2 victory.
Monaco's loss was be welcome news for John Isner, who is hoping to keep alive his slim chances of qualifying for the London tournament and stayed on course with a gruelling win over Kevin Anderson in a battle between the big servers.
Isner booked his place in the third round by beating South Africa's Anderson 7-6 (7/3) 6-7 (8/10) 7-6 (9/7) in two hours and 45 minutes in a match featuring 45 aces and no service breaks.
Croatian 10th seed Marin Cilic joined Isner in the third round after defeating Slovakia's Martin Klizan, the recent St Petersburg Open champion.
In first-round action there were straight-sets wins for Canada's 12th seed Raonic and Stanislas Wawrinka, the 13th seed from Switzerland. France's Gilles Simon knocked out Jurgen Melzer of Austria 6-4 6-2.
Australian teenager Bernard Tomic lost 6-4 6-0 to Florian Mayer, while China's Zhang Ze, who last week stunned Richard Gasquet in the China Open, could not produce fireworks for a second consecutive week, slipping to a comprehensive 6-0 6-2 defeat at the hands of Taiwan's Lu Yen-hsun.