THIRD ROUND LEADERBOARD:
-10 P Casey (Eng), B Dredge (Wal) -9 L Westwood (Eng) -8 R Karlsson (Swe), B Rumford (Aus)
Selected others: -7 A Quiros (Spa), O Wilson (Eng) -6 R Goosen (RSA) -5 N Fasth (Swe)
Casey is battling back to form from a rib injury sustained last season
Paul Casey joined Bradley Dredge at the top of the Qatar Masters leaderboard on 10-under par in ideal scoring conditions in Doha.
Casey shot a sublime bogey-free six-under-par 66 while Welshman Dredge recovered from a double bogey at the 5th for a two-under-par 70.
Lee Westwood heads the chasing pack on nine under, a shot ahead of Robert Karlsson and Brett Rumford.
Former champion Retief Goosen dropped just one shot in a 66 to go six under.
Scotland's Marc Warren is level with the South African, having shot six birdies in a round of 68.
Casey, 32, arrived in Doha still feeling the effects of a lingering rib muscle injury and having missed the cut in each of his three previous appearances at the tournament.
I am playing well now on a tough course where you cannot afford to make mistakes
But after his sparkling round, which included seven birdies for a 10-under total of 206, he admitted he was delighted with his return to form.
"I am still only 95 per cent fit with the rib and had no reason to be confident arriving here given my previous record on this course," Casey said.
"But I am playing well now on a tough course where you cannot afford to make mistakes and looking forward to the challenge of trying to win."
Dredge, who is looking for his first title since the 2006 European Masters, had briefly claimed the outright lead early at the start of the round with back-to-back birdies.
But he slipped back into the pack after being forced to chip out sideways on to the 5th fairway before two-putting after overshooting the green.
Rumford struggled to repeat Friday's brilliant 66 and reached the turn level par with Robert Karlsson and European number one Westwood two shots ahead.
Westwood also reached the turn at level par after finding water and double bogeying the par-three 8th, although he then recovered with birdies at the 9th and 10th.