He’s no longer so dependent on that fastest-on-tour serve and booming forehand. No longer in trouble when Plan A doesn’t work on a given day. And no longer a pushover on the red clay.

Stuck on his least-favorite court, at his least-successful Grand Slam tournament, and dealing with wet weather that figured to make matters worse, Roddick managed to lose serve seven times and still get by, beating Blaz Kavcic of Slovenia, 6-3, 5-7, 6-4, 6-2, yesterday to reach the third round at Roland Garros.

“It was brutal for me out there. I couldn’t get my serve to go anywhere, and the ball was just sitting up. I woke up this morning, looked out my window, and knew that it was going to be a long one,’’ the sixth-seeded Roddick said, referring to drizzles that delayed the start of play more than 4 1/2 hours.

“It kind of takes away a lot of shots,’’ he added, “and it makes it just about hitting the ball and running.’’

Roddick’s match was interrupted twice by showers on a day full of waiting, starting, and stopping. Despite the brief windows of tennis, there were plenty of developments:

■ 2008 French Open champion and former No. 1 Ana Ivanovic double faulted seven times and lost, 6-3, 6-0, to No. 28 Alisa Kleybanova in the second round. Ivanovic’s decline has been swift: She’s down to 42d in the rankings, is 10-10 this season, and has won two matches at her past three Grand Slam tournaments combined. Oddly enough, this was Ivanovic’s assessment: “I don’t think I played that bad, actually.’’

■ No. 17 John Isner of Tampa pounded 38 aces and came back to beat Marco Chiudinelli of Switzerland, 6-7 (3-7), 7-6 (7-3), 7-6 (9-7), 6-4, in a match carried over from Wednesday;

■ No. 4 Andy Murray and No. 25 Marcos Baghdatis, a pair of past Grand Slam finalists, won to set up a third-round matchup;

■ Unseeded Fabio Fognini of Italy was jeered by spectators when he walked on court, then closed out a 2-6, 4-6, 7-5, 6-4, 9-7 upset of No. 13 Gael Monfils of France in a match suspended at 5-all in the fifth set the previous night. Fognini riled the locals by arguing Wednesday with a tournament official about whether play should continue. As for the way he was greeted yesterday, Fognini said, “It’s normal; we are in France.’’

Three seeded women joined Monfils on the way out, all in straight sets: No. 8 Agnieszka Radwanska lost to Kazakhstan’s Yaroslava Shvedova, No. 21 Vera Zvonareva lost to Australia’s Anastasia Rodionova, and No. 32 Kateryna Bondarenko lost to Canada’s Aleksandra Wozniak.

Winners included No. 4 Jelena Jankovic, No. 5 Elena Dementieva, No. 11 Li Na, and No. 18 Shahar Peer.

“Overall, it was very difficult because of the conditions,’’ said Jankovic, who struggled in a 6-2, 3-6, 6-4 victory over Kaia Kanepi, a qualifier from Estonia ranked 118th. “I came here around 9 in the morning. To be waiting around in the locker room, it’s really not easy.’’

When play was suspended last night because of darkness — there are no lights on the courts at Roland Garros — Justine Henin and Maria Sharapova were leading their matches, while unseeded American Mardy Fish was tied at a set apiece with No. 14 Ivan Ljubicic of Croatia.

There were 18 singles matches that never began, so players such as four-time champion Rafael Nadal and 2002 champion Serena Williams won’t hit a shot in the second round until what shapes up to be a busy day today.

Roddick will get a chance to rest today after spending nearly all of yesterday at Roland Garros, including about three hours at Court Suzanne Lenglen with the 112th-ranked Kavcic, who is only 1-2 at major tournaments.

Roddick won the 2003 US Open and ended that season at No. 1 in the rankings. He’s yet to add a second Grand Slam title to his résumé, and has lost to Roger Federer four times in major finals, capped by last year’s 16-14 fifth-set setback at Wimbledon.

Since hiring coach Larry Stefanki before last season, Roddick has varied his game and improved his fitness. Which is why, even though he missed much of April and May, and came to the French Open without a single tuneup clay-court match, he said with a straight face: “I have kind of a confidence just getting through matches right now.’’

Even at Roland Garros, where he won a total of two matches from 2002-08, often bidding adieu on the very court he was assigned yesterday.

“I’ve lost a lot matches out there on conditions exactly like today,’’ he said. “That was one that might have gotten away from me a while ago, but I was just kind of staying the course. I don’t know the last time I lost serve seven times and won.’’