France's Gael Monfils said he was targeting a return to the top 10 as he stepped up his strong return from injury with a 6-4, 2-6, 7-5 win over Kevin Anderson in the Thailand Open first round on Wednesday.
Later in the day, the top seed Janko Tipsarevic strolled into the quarter-finals as he saw off Japan's Hiroki Moriya 6-4, 6-4 in their second-round clash.
Finnish seventh seed Jarkko Nieminen, a former finalist, also reached the last eight as he beat German Philipp Petzschner 7-6 (7/1), 6-2.
Monfils, who had been out since May with right knee trouble but reached the semi-finals in his comeback event last week in Metz, said his injury woes had given him a "new mindset".
"It's really tough to focus again, that is the biggest thing," said the unseeded Monfils, now ranked 45. "It was four tough months for me, I didn't know when I would be back on the court. That is tough on the mind.
"I've been in the top 10 and I'm motivated to be there again, it's a new start for me. I have new goals, a new mindset and mentality."
Monfils dealt with momentum shifts in his contest with South African Anderson, who had to play qualifying rounds despite his 35th ranking after forgetting to formally enter the indoor event in Bangkok on time.
The Frenchman claimed the opening set but could not close out the quick win, with Anderson levelling the match at a set each. In the third they swapped breaks before Monfils broke again in the penultimate game with a sizzling pass.
He closed out victory on his first match point a game later in just under two-and-a-half hours.
"It was a long time that I didn't play. I need a lot more tennis. I played OK, but just enough to win today," said Monfils, who has 18 victories this season against eight defeats.
The Serb Tipsarevic was rarely troubled by Moriya, who was playing in only his third ATP match.
"I liked most of my game during the match," said Tipsarevic. "Let's just say I came in ready. Winning in straight sets was good enough, I'm happy to be in the quarter-finals."
Towering Croatian Ivo Karlovic reached the second round as he beat Australian Marinko Matosevic 6-3, 6-4, while Japan's Go Soeda disappointed home fans with his defeat of Thai Danai Udomchoke 6-4, 7-5.
The home favourite is the only player to have competed in each of the 10 editions of the ATP event.