SOUTHPORT (AFP) — Rory McIlroy said the recent UK heatwave that has transformed conditions ahead of this week’s British Open is a “double-edged sword.”

Players who often lag behind their rivals for driving distance may now see their shots getting extra run on the fairways of a Royal Birkdale course in northwest England baked hard and fast by soaring temperatures.

But equally, anyone wayward off the tee may not face the same consequences of what McIlroy said Wednesday was the once “penal rough” of a few weeks ago.

“I think it’s a double-edged sword,” said McIlroy, who will begin his quest for a second British Open title that fired off on Thursday (Manila time) after triumphing at nearby Hoylake back in 2014.

The 37-year-old Northern Irishman, the reigning US Masters champion, added: “All this dry weather and sun and a little bit of wind is obviously great for the course in one way, but when I was here a couple weeks ago the rough was a lot more penal than it’s going to be this week. It’s definitely burnt out a lot.”

“The big thing, especially off the tee here, is avoiding the fairway bunkers. You might see some guys being more aggressive off the tee, taking driver, trying to take the fairway bunkers out of play.”

“It might be in the rough, but it’s not that penal, so you get a wedge in your hand and you can figure it out from there,” explained McIlroy, one of just six golfers to have completed the career Grand Slam of major titles — the British Open, US Open, US Masters and US PGA.

The British Open is played on a links or coastal course, with defending champion Scottie Scheffler’s most recent experience of those conditions seeing him miss the cut — the American’s first in four years — at last week’s Scottish Open.

“The ball’s just going to run forever pretty much (at Birkdale),” Scheffler, 30, said Wednesday.

“There’s a lot of thinking off the tee on whether you want to just hit driver up there somewhere and play from the rough most likely or start hitting some irons, getting it in some fairways and hitting some longer shots into the greens.”

“If it wasn’t as firm as it is now there wouldn’t be as much decision-making but with the firmness it creates a whole lot more challenges just to try to control your ball and figure out where it’s going to end up.”