Rafael Cabrera-Bello saw his overnight two-shot advantage at the Qatar Masters wiped out as Steve Webster moved into a share of the lead.
The Spaniard was 13-under-par after the second round but found life more difficult on Friday, carding a one-over 73 to relinquish sole leadership of the tournament heading into the final day.
Cabrera-Bello's day started well with a birdie at the second, and although he dropped a shot at the sixth he was back to 13-under by the 10th hole.
However, bogeys at 13 and 15 saw him finish the day level with Englishman Webster at 12-under, the latter having gone round in 70.
Thomas Aiken of South Africa, Denmark's Thorbjorn Olesen and France's Adrien Saddier, who surged into contention with a 64, are just one shot behind on a congested leaderboard, with five further players two shots off the lead.
"It was a tougher day today; things did not go as great as they have been so far," Cabrera-Bello admitted after his round.
"I still feel as though I played okay, I just did not manage to score as well. It was tough with the wind, I didn't quite make the putts and struggled here and there with my chipping, but overall I got the not-so-good round out of the way and I am still in a fantastic position going into Saturday."
Webster, three shots behind Cabrera-Bello at halfway, made bogeys at the fourth and fifth on Friday but responded with four birdies to reach the summit.
"I don't know what happened the first six or seven holes," the 39-year-old said.
"I hit it really well on the range and I think I got a bit cocky on the course and hit so many bad shots the first six or seven holes; it was like I had never played golf before.
"On the back nine I gave myself a few chances and I knocked in a really good putt on 11, which made things feel a little better.
"But the pins were tucked away a bit and that's why the scores have pretty much stayed the way they were"
Saddier's flawless 64, which featured six birdies in the first seven holes, represented the best round of the day by a comfortable margin.
The 21-year-old is playing in just his fourth European Tour event after coming through qualifying school.
A total of 19 players will begin the final day within four shots of the lead.