Rory McIlroy endured a frustrating day on the greens at the Dubai Desert Classic on Friday, but he still reached the tournament’s halfway stage with a one-stroke lead.

The Ulsterman struggled off the tees early on in his second round, but by the turn he had briefly eased three strokes clear of the field, only for his putting woes and a charge by rising US star Brooks Koepka to keep him in check.

McIlroy had a 70 to stand at 11-under for the tournament, with Koepka, a year younger than McIlroy at 23, equalling the day’s best round of 65 to get to 10-under.

Two strokes further back on eight-under came Damien McGrane (70) of Ireland, Englishman Danny Willett (65) and Julien Quesne of France (70).

Defending champion Stephen Gallacher of Scotland (71) and European No.1 Henrik Stenson (67) of Sweden were among those on seven-under.

It was another disappointing day for Tiger Woods, who struggled with the putter all the way en route to a 73, which left him eight shots adrift of playing partner McIlroy and well down the field.

Looking to make it two wins and a second place in his last three tournaments, McIlroy had the luxury of taking the morning off watching to see whether anyone could overhaul him after his stunning nine-under 63 on Thursday.

Several challengers came and went, especially McGrane, Willett and Italian Ryder Cup star Edoardo Molinari.

Koepka, who opted to play on the European Tour Challenger circuit after graduating from his US college in May, 2012, was flawless with seven bogeys in his 65.

Woods, playing in his second tournament of the year after missing the final cut at Torrey Pines last week, never looked like getting fully into his stride, despite an encouraging birdie at the third.

Three-time former winner Ernie Els was also in better nick with a 70, but at level par for the tournament, the South African was just outside the projected cut mark.