Top seeds Roger Federer and Andy Roddick reached the Thailand Open semi-finals with straight-sets wins on Friday.
Federer overcame Swedish number eight seed Robin Soderling 7-6, 6-4, and Roddick cruised to a 6-3, 6-4 win over former Australian Open champion Thomas Johansson.
The key to both victories was the serve, with Federer hitting his 14th ace to complete victory over Soderling, and Roddick ending Johansson's hopes with his 21st ace.
Soderling initially struggled to sustain long rallies against the Swiss world number one, but ultimately made Federer work for his 67th win of the season. He served strongly and comfortably dealt with his opponent's sliced crosscourt backhand with ease.
Soderling played well enough to break for a 5-4 lead but Federer raised his game and the Swede was unable to serve out the set. Three exchanges of serve from 1-1 in the second set were enough to see Federer through.
"I had a tough time breaking him up until the time he served for the set, which was obviously very important," Federer told reporters.
"He was playing really well and was making me work quite hard.
"It's always good to win in straight sets. Especially today, I thought he was the toughest opponent I've played so far in the tournament. It was tough all the way to the end."
Roddick's power game left him comfortably in control against Johansson, although the outcome was decided by just one break in each set.
The second-seeded American broke for 3-1 in the first set when Johansson netted a backhand, and for 5-4 in the second when Roddick's pace forced the Swede to hit a forehand wide.
