SAN JOSE -- No singles player in this year's SAP Open field has accomplished more on a tennis court than Lleyton Hewitt. The Australian has 28 tournament championships on his resume, including one in San Jose.

But Hewitt is 31 now and a long way from the days when he was the sport's top-ranked player.

And winning, even in the early rounds, is a chore.

Tuesday, Hewitt lost the first set and trailed by a break in the second against Blaz Kavcic of Slovenia. But the former U.S. Open and Wimbledon champion charged back to win the opening-round match 3-6, 6-4, 7-6 (4) at HP Pavilion.

"There were a lot of momentum changes throughout the match," said Hewitt, now ranked 112th. "He's a tough competitor out there. It wasn't easy. In the end, I was happy to get through."

Hewitt's victory came in the second match of the day session, hours before the world No. 1 doubles team of Bob and Mike Bryan stepped on the court for the featured evening match.

The Bryan twins, who starred at Stanford in the 1990s, have won 84 doubles titles on tour, including a record 13th Grand Slam at the Australian Open last month. But they have never won the SAP Open in nine previous appearances and did not have an easy time in their opening match against wild cards Steve Johnson and Jack Sock, ultimately surviving 7-6 (3), 7-6 (5).

Sock and Johnson had a chance to serve out the opening set but a double fault and two poor shots -- all by Sock -- evened the match 6-6. The Bryans won the tiebreaker and then escaped another one in the second set to close out the 1-hour, 25-minute match.

"We had to sneak it out," Mike Bryan said.

Added Bob, "They were eager and really gunning for us. We had our hands full, and I thought we started to play really well there and fought them off."

The Bryans are treating this week as a homecoming. They visited their former stomping grounds at Stanford and had Stanford friends in the stands Tuesday.

"Stanford was definitely two of the most fun years we've had playing this game," Bob Bryan said. "To go back there and look at that stadium court, where we had so many great memories, is awesome. We went to the Stanford gift shop and dropped a few hundred dollars on Stanford gear to take home."

The day session also included seventh-seeded Marinko Matosevic's 7-6 (5), 6-1 win over Sock, and Benjamin Becker's 6-7 (3), 7-5, 6-3 victory over Ryan Harrison, a semifinalist in San Jose last year, was ill last weekend but did not use that as an excuses, his first loss in three matches with Becker.

Denis Istomin, who lost to Milos Raonic in last year's final, closed the day session with a 6-3, 6-4 victory over American qualifier Ryan Sweeting.

American qualifier Tim Smyczek defeated Fernando Verdasco 6-3, 6-3 in the late match.