In-form Austrian Bernd Wiesberger shot a second successive round of 65 to edge ahead of Ross Fisher and top the leaderboard with one round to play at the Portugal Masters.
Fisher had led the chasing pack at the halfway stage in Vilamoura but saw his three-shot lead taken away by an impressive Wiesberger.
The Austrian produced six birdies in seven holes to join Fisher on 13-under par going into the final hole of the day.
A persistent ankle injury took its toll on Fisher late in the round and the former Ryder Cup player's day was compounded when a par putt lipped out on the 18th green.
Richard Finch, Shane Lowry and Michael Campbell lead the chasing pack behind Fisher in joint-third place, sitting four shots away from Wiesberger on nine-under.
Spanish veteran Miguel Angel Jimenez also remains in contention going into the final round on eight-under.
