Andre Agassi kept up his devastating form at the Australian Open with a 7-6 6-3 6-4 win over Paradorn Srichaphan.
Srichaphan had beaten Agassi in their only previous meeting at Wimbledon in 2002 and had five chances to take a one-set lead on Rod Laver Arena.
But defending champion Agassi raised his game when it mattered and after taking the set on a tiebreak, cruised through the remaining two.
Agassi next takes on Sebastien Grosjean, who beat Robby Ginepri.
"I had to be executing everything pretty well," said Agassi.
"Against Paradorn I am much better if I am doing everything well and nothing spectacular. You can't give him a lot of looks."
The American remains on course for a dream semi-final with world number one Andy Roddick.
"I feel like I've experienced every part of my game throughout this first week and I've liked the levels I've hit," Agassi said.
"I'm in position to go further, to take it higher, but again you've got to come out and execute every day.
"So I think when it's asked of me, I'm going to give it a good go."
Grosjean shot down the challenge of rising American star Ginepri in four sets.
The players, who both showed consistency in their serving from the start, shared the opening two sets.
But after Grosjean sealed the third by breaking in the 10th game, it had a devastating effect on the number 32 seed.
The Frenchman broke Ginepri's first service game and wrapped up the set in 23 minutes to finish 6-4 3-6 6-4 6-1.