(CNN) -- Sergio Garcia crashed out of contention on the opening day of the World Match Play Championship in Spain, while top seed Paul Casey's comeback ended with two defeats.
Both players have been as high as No. 3 in the world, but neither will have anything to play for in Friday's final round-robin matches at Finca Cortesin near Marbella.
Fourth seed Garcia, who has fallen to 10th in the rankings this year, lost by one hole to England's Oliver Wilson and could only halve with Australian Robert Allenby after a birdie at the last hole.
Wilson was top of Group B after also beating Martin Kaymer by one hole, with the German knocked out of semifinal contention as he lost to Allenby by that same margin.
Wilson's compatriot Casey made his long-awaited return from the rib problem which has sidelined him since the start of August, but suffered a one-hole defeat by world No. 168 Scott Strange of Australia and then went down by three against Anthony Kim.
American Ryder Cup star Kim topped Group A with two wins after also defeating two-time major winner Retief Goosen of South Africa by an impressive four holes.
Goosen, who faces Kim on Friday, kept his hopes alive by beating Strange by one hole.
Casey said he was still being hampered by his injury.
"I can't swing the way I want. I'm coming out of a lot of the shots. Scott played well, but having said that, I gave him three holes on the front -- and you can't do that against anybody in this field," the world No. 4 said.
The players in Group C and Group D played only one match each on Thursday, so second seed European Ryder Cup star Lee Westwood will have the chance to bounce back from his crushing six-hole defeat by India's Jeev Milkha Singh.
Singh topped Group D ahead of England's Ross Fisher, who beat seventh seed Camilo Villegas of Colombia by two holes.
Masters champion Angel Cabrera headed Group C following his five-hole victory over Rory McIlroy of Northern Ireland.
Third seed Henrik Stenson suffered a shock loss in the other game, losing by three holes to England's Simon Dyson.
The tournament, which was not staged in 2008, has moved to Spain this year from its traditional home at Wentworth in England, with a change of format from the previous knockout matches.
The 16-man field is divided into four groups of four players, with those finishing top progressing into the 36-hole semifinals on Saturday.
Whereas matches used to end when an unassailable winning margin was achieved, this year the round-robin matches will go to a full 18 holes no matter the score.
Sunday's final will also be played over 36 holes.
The 2007 winner, Ernie Els, is one of several leading players playing in the Singapore Open this week.
The South African was tied for second with Chinese Taipei's Yin-Shin Chan after a four-under-par 67 in Thursday's opening round, which was cut short by bad weather.
England's Ian Poulter led with a 66 before a three-hour rain delay left half of the field unable to complete their first rounds.
World No. 2 Phil Mickelson was in a group tied for seventh after completing a 69, while three-time major winner Padraig Harrington was level par after 10 holes.
Meanwhile, the opening round of the U.S. PGA Tour's penultimate tournament this season, the Viking Classic in Mississippi, was abandoned due to heavy rain on Thursday.
The field, many of whom are still seeking to retain playing rights for next year, will begin their first rounds on Friday at the Annandale Golf Club in Madison, but more bad weather is forecast.