The American tandem of U.S. Open winner Jim Furyk and Justin Leonard shot a 2-under 70 in Friday's foursomes, or alternate-shot, format. The French team of Raphael Jacquelin and Thomas Levet notched an even-par round of 72 at the Ocean Course at Kiawah Island Resort.
Saturday's action will be four-balls, or best-ball, but the format returns to alternate shot for Sunday's final round.
The German team of Alex Cejka and Marcel Siem, who led after the first round, struggled badly in Friday's second round. They teamed for a 5-over 77 and are tied for sixth at even-par 144.
Sabbatini and Immelman combined for two birdies on the front nine on another day when the Ocean Course showed its teeth. The wind that wreaked havoc on play on Thursday was not up on Friday but the course was still was demanding.
Sabbatini drove to the right side of the fairway at the 12th and Immelman knocked a shot from 194 yards out to 10 feet. Sabbatini drained the putt to take a one-shot lead at 5 under par but trouble loomed for the South Africans.
At the 13th, Sabbatini miscalculated the wind and hit a 4-iron into the reeds. Immelman did the best he could but the team managed a bogey and fell into a tie for the lead.
The South Africans took sole possession of first place on the leaderboard thanks to some serious bunker problems by the German team. It took Cejka and Siem three chances to get out of a fairway bunker at the 13th and they left with a double bogey, which included a 12-footer for the save by Siem.
Germany went two-over the rest of the way to plummet down the leaderboard.
The South African duo stayed steady. At the par-3 17th, Immelman hit a solid tee ball that landed 40 feet from the hole. Sabbatini got a good read on the putt and sank the long birdie try to reach 5 under par.
'That was kind of an unexpected one,' admitted Sabbatini, who won this year's FBR Capital Open on the PGA Tour. 'That's a hole that you are quite happy to make a three on, let alone in alternate shots. We picked one up on the field there for sure.'
They parred No. 18 to take a two-shot lead into Saturday.
'All in all, that was probably one of the best rounds I've played all year,' said Immelman, playing in his first World Cup. 'We played real solid all day and putted well too.'
The Americans birdied the par-5s on the front nine, two and seven, but Leonard, who finished second on the PGA Tour in putting, lipped out a two-footer for a bogey at the eighth.
The U.S. team had birdie putts inside 10 feet at 10 and 11 but failed to convert on either. They made their final birdie of the round at the par-5 16th when Furyk cashed in a five-footer.
'Overall, the second best round of the day, so I'm pleased with the way we played,' said Furyk. 'We want to go out there and keep it up, keep the momentum going and have a good weekend.'
The French pair had problems early with a double bogey, two bogeys and two birdies over their first 10 holes. They combined to birdie two of their final four holes to join the Americans in second.
'Both Thomas and I had a good feeling on the greens and we know that playing well in the foursomes is the key to the week,' said Jacquelin. 'After the first two days we are quite confident.'
Wales, in second after day one, are still in the hunt. Ian Woosnam, a last- minute replacement for Phillip Price, and Bradley Dredge shot a 2-over 74 but are alone in fourth at 2-under-par 142.
Argentina's Eduardo Romero and Angel Cabrera posted a 1-over 73 and are in fifth place at minus-1.
Germany was joined in sixth place by Sweden's Niclas Fasth and Fredrik Jacobson (72) and 1999 British Open winner Paul Lawrie and Alastair Forsyth of Scotland.
Japan, the defending champion, recovered from Thursday's 74 with a 1-under 71 on Friday. Shigeki Maruyama and Hidemichi Tanaka share ninth place with Michael Campbell and David Smail of New Zealand and Paraguay's Carlos Franco and Marco Ruiz at plus-1.