Kitzbuehel - Former world No 1 Thomas Muster was easily beaten 6-3, 6-0 by Philipp Kohlschreiber at the Bet-at-Home Cup on Monday in the latest match of his comeback.
The 43-year-old Austrian returned to professional tennis in 2010 after 11 years away, but has won only one of 15 main-draw matches on the lower-level Challenger tour and lost both main-draw matches at ATP level. He is still ranked outside the world's top 1 000.
"I don't plan to keep on playing forever but I am still very much enjoying it," Muster said.
Muster, who won the French Open in 1995, was on his favourite clay-court surface against Kohlschreiber, but the fifth-seeded German raced into a 3-0 lead before Muster managed a break and reduced the deficit to 3-4 shortly afterward.
Kohlschreiber did not concede another game and converted his first match point after just over an hour of play.
"To lose the second set 6-0 is fine with me," Muster said. "It just shows that Philipp did not give away any points."
Kohlschreiber, who won his third career title in Halle in June, will next play Albert Montanes, who defeated fellow Spaniard Javier Marti 6-3, 6-2.
Earlier, Spain's Albert Ramos beat Igor Andreev of Russia 6-0, 6-7 (2), 6-4 to reach the second round.
Ramos, coming off his first career semi-final in Umag, Croatia last week, will next play eighth-seeded fellow Spaniard Pablo Andujar, who rallied to beat Lukas Rosol of the Czech Republic 3-6, 6-3, 6-3.
Two more Spanish players advanced after Pere Riba downed Romania's Victor Hanescu 7-6 (3), 6-4, and Daniel Gimeno-Traver defeated wildcard Dominic Thiem 6-4, 6-2 in the Austrian's first match on the ATP World Tour.
Results from the first day of the ATP event on Monday (x denotes seeding):
Philipp Kohlschreiber (GER x5) bt Thomas Muster (AUT) 6-3, 6-0
Andreas Seppi (ITA x6) bt Denis Istomin (UZB) 6-2, 6-2
Daniel Gimeno (ESP) bt Dominic Thiem (AUT) 6-4, 6-2
Albert Montanes (ESP) bt Javier Marti (ESP) 6-3, 6-2
Pablo Andujar (ESP x8) bt Lukas Rosol (CZE) 3-6, 6-3, 6-3
Albert Ramos (ESP) bt Igor Andreev (RUS) 6-0, 6-7 (2/7), 6-4
Pere Riba (ESP) bt Victor Hanescu (ROM) 7-6 (7/3), 6-4