Shane Lowry fired a superb second round of 65 at the season-ending DP World Tour Championship in Dubai to claim a share of first place on 10 under par, alongside John Catlin of the United States and England's Sam Horsfield, but a double-bogey on the final hole cost Rory McIlroy the outright lead on the Earth Course at Jumeirah Golf Estates.

McIlroy held a two-shot lead after an opening 65 and covered the first nine holes of his second round in three under, but that was not enough to keep his nose in front.

Ryder Cup team-mate Shane Lowry was already four under for the day when he chipped in for an eagle on the 14th, and a birdie on the next took him alongside McIlroy on 10 under par, with Horsfield making it a three-way tie at the top.

A 347-yard drive on the 10th left McIlroy with just 63 yards to the pin, but after a mediocre approach the Holywood star three-putted for a second bogey of the week.

However, the former world number one bounced back immediately by chipping in for birdie from the back of the 11th green to get back to 10 under.

Lowry had set the clubhouse target on that mark after completing a bogey-free 65.

Horsfield took the outright lead with a birdie on the 14th, only to miss from close range for another on the next and then drop shots on the 16th and 17th.

McIlroy had to scramble for par on the 15th following a wayward drive and then birdied the 16th to edge back in front on 11 under.

However, he then drove into a fairway bunker on the 18th and, after laying up, compounded the error by firing at the pin and pulling his approach into the creek which runs the length of the hole.

The resulting double-bogey seven dropped McIlroy to nine under par and a shot behind the halfway leaders.

Open champion Collin Morikawa strengthened his grip on the Race to Dubai title with a second consecutive 68 to reach eight under, two shots off the lead.

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Reflecting on his round – and that sublime shot on the par-five 14th – Lowry told Sky Sports: "Yeah, that was one of my better ones. That was top drawer. That was as good a chip as I hit in a while.

"I knew when I missed it over there it was going to be difficult and I would have been happy to get it within 10 feet, but it came out lovely and hit the flag and went in, which was a Brucey bonus."

The Clara man finished fourth in the Alfred Dunhill Links Championship immediately after making his Ryder Cup debut in September, but has since finished 54th in a 78-man field in Las Vegas and missed his last two cuts.

"I've struggled the last few weeks," the former Open champion admitted. "In hindsight, I should have taken a few weeks off and just come here and tried to perform as best I can.

"I spoke to Westy (Lee Westwood) last week, I spoke to Tyrrell (Hatton) and he said after France he really struggled for a few months. It’s something that I wasn’t aware of.

"Since I won the Open at Portrush I’ve spent the next two years trying to make the Ryder Cup team and I’ve reached that, I felt like I left it all at Whistling Straits and then I came back out and I’m just running on fumes.

"Thankfully I’m near the top of the leaderboard this weekend and it will give me something to go out and fight for."

A frustrated McIlroy said afterwards: "I hit that tee shot (on 18) really well. I actually didn't expect it to go as far as it did and get up into the face of the bunker.

"And then the third shot, I hit a really good shot. That part of the fairway where the ball was, was quite just sort of thatchy and came up spinny into the wind.

"I hit a good golf shot and felt like I didn’t deserve to be in the water and it was a tricky up and down from there. It wasn’t the greatest way to finish and I was just sort of holding it together most of the day.

"It would have been nice to finish off a bit better but I’m still right in the golf tournament. I still feel like I played well and I feel like 70 is sort of the worst I could have shot today, especially with the finish and hopefully that’s the bad one out of the way."