HANOVER, Germany (AP) _ Pete Sampras took advantage Wednesday of a format that offers losers a second chance and stayed on course for his fourth ATP Tour World Championship title.

Rebounding from a surprise three-set loss to Carlos Moya a day earlier, Sampras downed big-serving Greg Rusedski 6-4, 7-5.

``Yesterday, I really felt flat, mentally and physically,'' said Sampras, the defending champion and world No. 1. ``I had a lot more energy today.''

The $3.3-million tournament brings together the top eight players in the world, split into two groups. The top two from each group advance to the semifinals.

Because of the round-robin format in the groups, Sampras didn't have to pack his bags after losing to Moya.

In each of the three years he won the title, Sampras lost a match in the round-robin portion of the event.

``Things are definitely looking a lot better,'' said Sampras, who could have been eliminated by another loss.

After making 50 unforced errors against Moya, Sampras made only nine against the Canadian-born lefthander.

``Coming into the match, I knew it was make it or break it,'' said Sampras, whose tour-leading seven titles this year include Wimbledon and the Australian Open.

``I returned well against one of the biggest servers, I played a very solid game today. I felt like a new player.''

In a match featuring two newcomers to the elite season-ending tournament, Yevgeny Kafelnikov beat Jonas Bjorkman 6-3, 7-6 (8-6).

Patrick Rafter, the No. 3 in the world, needed only 56 minutes to beat Moya 6-4, 6-2. Rafter had never beaten Moya in three previous career matches.

Sampras and Rafter will have a day off and play each other Friday.

Rusedski blasted an ace for a promising start of the match, but dropped his serve after a couple of volley errors in the fifth game.

Just before serving for the set, Sampras needed a three-minute timeout to stop a nose bleed. But it didn't affect his game.

``He came out and served better,'' said Rusedski, who began the year ranked No. 48 and has shot up to No. 5. The U.S. Open finalist is the first British representative in the history of the tournament.

Regardless of the outcome of the tournament, Sampras is assured of finishing as No. 1 in the world for the fifth straight year, a record he shares with Jimmy Connors.

On Thursday, Moya plays Rusedski, while in the other group, Michael Chang meets Kafelnikov and Sergi Bruguera battles Bjorkman.