Jamie Donaldson edged ahead of Lee Westwood and Rory McIlroy on Saturday to lead after three rounds of the European Masters.
Donaldson, chasing a first career victory, shot a 6-under 65 to head the leaderboard at 14 under, one shot clear of Westwood with McIlroy a further stroke back in third.
''I'm the underdog in effect even though I'm winning by one,'' Donaldson said of Sunday's final group. ''It's awesome. You are playing with two of the greatest players at the moment.''
Second-ranked Westwood had seven birdies, including at all four par-5s, and no dropped shots in a 64 that was the day's best.
''It's always nice to play a round with no 5s and no bogeys, especially on a course like this that can trip you up,'' Westwood said.
McIlroy began the day in a four-way share of the lead at 8 under, but dropped shots at the 16th and 17th in his 67.
''It wasn't the greatest way to finish but I'm still in there,'' said the U.S. Open winner, who has targeted the world No. 3 slot with a victory here.
Thomas Bjorn of Denmark, last week's winner at Gleneagles, Scotland, had a 66 to be 11 under alongside Gary Boyd of England.
Fifth-ranked Martin Kaymer of Germany is among six players on 10 under, trailing Donaldson by four shots.
Playing in an unheralded final three-player group with Boyd and Simon Dyson, Donaldson shot seven birdies with a single blemish in his round - a six at the 629-yard (meter) ninth.
''I played really good all the way round,'' said the 35-year-old Donaldson, who has two runner-up finishes on the European Tour, most recently at Malmo, Sweden in July 2009. ''I will go out (Sunday) with the exact same game plan.''
Westwood's round included four straight birdies between the sixth and ninth holes.
''They are scoring holes,'' said Westwood, who fought a heavy cold despite another sun-baked day at altitude in the Swiss Alps. ''I tried to hit in sensible places all day and try not to make mental errors.''
McIlroy birdied the first and sixth then sank a 40-feet putt for an eagle two at the scenic seventh hole. He got back-to-back birdie-4s after the turn, before his putting let him down at the par-3 16th.
''There's a 61 or 62 out there,'' said McIlroy, who lost a playoff here at age 19 when taking a four-shot lead into the final round.
''I should have won here in 2008 and I feel I should be leading this tournament by a bit already,'' McIlroy said.
Kaymer lamented another day of missed chances at holes five through seven, though the former top-ranked golfer remains in contention.
''I am level par for the tournament at those three easy holes and Rory is six under for them,'' Kaymer said. ''I'm playing very well and need to be very, very patient.''
