The 22-year-old Australian was playing for the second straight day against a journeyman American in his first tournament since losing in the opening round at Wimbledon.

"I felt I didn't serve that great yesterday so I came out here and tried to work on it," said Hewitt.

"It is a heck of a lot easier to take control when you are serving aces."

Hewitt suffered a shocking early exit at this year's Wimbledon, losing to Croatian qualifier Ivo Karlovic.

Hewitt, the 2002 Wimbledon winner, had one minor letdown in Wednesday's one hour, 11 minute match when he lost his serve to go 3-3 in the first set.

"I took my foot off the pedal at stages but I felt I was in control of the match," he said.

It was a more polished performance than the spotty play that marked Tuesday's tournament 6-0, 7-5 win over American Cecil Mamiit.

"I got through my first two matches reasonably well and won both in straight sets. I have to try to keep it going."

Hewitt will face Denmark's Kenneth Carlsen in the quarterfinals.

"I got a day off tomorrow then I have to get ready for Carlsen," said Hewitt.

The 30-year-old qualifier Joyce was coming off his first ATP win of the season, a three-set victory over American Jan-Michael Gambill.

Joyce's biggest career victory came in Los Angeles 1995, when he upset then-world No. 1 Jim Courier in the second round.

Germany's Nicolas Kiefer scored the biggest upset of the tournament so far, beating Dutchman Sjeng Schalken 6-4, 6-4 on Tuesday.

"It was great win for me," said Kiefer. "I moved good on the court and served well so I think my game is coming around step by step."

Kiefer raised his record against third seed Schalken to 3-0, having beat him twice previously in 2000 in Qater and at the US Open. Kiefer has won all three matches against Schalken in straight sets.