With Paul Lawrie's driving let him down as he crashed five and four to 47-year-old Zimbabwean Mark McNulty, Britain's only survivor is their fellow Scot Andrew Coltart.

Again showing his liking for all things Australian - two of his three professional victories have come Down Under - Coltart followed up his three and two win over Phillip Price by beating ninth-seeded American David Toms by the same margin.

Coltart now meets the tournament's other 47-year-old, 1982 Masters champion Craig Stadler, for a place in the quarter-finals. Another win would guarantee the 30-year-old over £100,000 and keep alive his hopes of the £668,672 first prize.

All was going well for Orr as he took a two-hole lead at the 13th and then hit his approach to four feet on the next.

Leonard was 30 feet from the flag, but holed for a half and birdied the next as well to halve the deficit.

Then the horror show started for the Helensburgh golfer on the 474-yard 16th, however. After Leonard had hooked into the trees, hacked out sideways with his putter and then failed to make the green in three Orr, from the middle of the fairway, pulled his second into a bunker.

Leonard chipped dead for a bogey five and Orr thinned his recovery into another trip, came out 20 feet past the flag and missed that putt to lose a hole he was odds-on to win.

By three-putting the 17th he was suddenly one down and after staying alive by making an eight-foot second putt on the 18th and seeing Leonard miss from six feet there and again on the first extra hole Orr found more sand on the short second.

This time he was plugged and again he went flying over the green before leaving his chip back 30 feet short. When he missed that he conceded defeat to the Texan, who had played only one shot on the hole.

"I thought I was almost there on the 14th, but that's match play," he sighed. "It's disappointing, but you can only do your best. I didn't play very well - and he played very poorly.

"I probably should have hit one less club into the 16th. I didn't think it was the end of the world going into the bunker, but the ball ran onto the downslope and there was no sand underneath."

Coltart was an approximate five under par for the second day running, but even though he went to the turn in 32 he was still on level terms with Toms.

Then came the shot which filled him with confidence, a 235-yard five-wood into the long 12th that stopped a foot from the flag for a conceded eagle.

Toms then made it easier than Coltart could have expected, though, by bogeying the 14th, 15th and 16th to go out.

"Getting here last week has paid off," said Surrey-based Ryder Cup player, who was sixth on the same Metropolitan course in the 1997 Australian Open won by Lee Westwood.

Asked if there was anything about Australia which made him play so well he replied: "I just like the courses and psychologically I think that makes a difference.

"But I also think I will need to play better tomorrow." He will be favourite, however, as Stadler has slid to 92nd in the world and was originally the 28th reserve for the tournament.

Lawrie did eagle the 516-yard fourth to lead McNulty, but almost hooked his drive out of bounds on the next, then after McNulty had birdied the short seventh he sliced into the trees at the eighth.

McNulty had another two on the ninth to turn three-up, needed only a par at the next and closed the match out with another birdie at the 349-yard 14th.

Top seed Ernie Els battled back from three down - it was very nearly four - to put out Japan's Hidemichi Tanaka on the last and now plays Jean Van de Velde, whose hopes of a second Ryder Cup cap were further boosted by a four and three win over another South African, Retief Goosen.

The only other European left in is Pierre Fulke, the Swede who won the Volvo Masters in November and is now close to securing a Ryder Cup debut.

Fulke beat American Glen Day at the 20th and now plays New Zealander Michael Campbell.

Shock of the day was the defeat of third seed Vijay Singh. Four down at the turn to Japan's Toru Taniguchi, the Fijian cut it to one, but lost on the last.