Rory McIlroy admitted chasing Bryson DeChambeau's power cost him after the four-time major champion comfortably missed the cut at The Players Championship as Lee Westwood produced a flawless performance to lead the way.
DeChambeau's power play at last year's U.S. Open has changed golf for many across the PGA and European Tours, with former world number one McIlroy trying to add length to his game.
But defending Players champion McIlroy, without a win since 2019, missed the cut by 10 strokes on Friday – a second-round 75 adding to his opening 79 at TPC Sawgrass.
After another forgettable day, which included a double-bogey, three bogeys and two birdies, McIlroy explained his struggles, telling reporters: "Probably, like October last year, doing a little bit of speed training, started getting sucked into that stuff, swing got flat, long and too rotational.
"Obviously I added some speed and am hitting the ball longer but what that did to my swing as a whole probably wasn't a good thing. So I'm sort of fighting to get back out of that. That’s what I'm frustrated with."
McIlroy added: "I'd be lying if I said it wasn't anything to do with what Bryson did at the US Open. I think a lot of people saw that and were like, 'Whoa, if this is the way they're going to set golf courses up in the future, it helps. It really helps'.
"The one thing that people don't appreciate is how good Bryson is out of the rough. Not only because of how upright he is but because his short irons are longer than standard, so he can get a little more speed through the rough than us, than other guys.
"I thought being able to get some more speed is a good thing and maybe just to the detriment a little bit of my swing, I got there. I just need to maybe rein it back in a little bit."
Westwood had no such trouble during the second round – the Englishman using a six-under-par 66 to earn a one-stroke lead at nine under before darkness suspended play.
After finishing second at last week's Arnold Palmer Invitational, Westwood roared to the top of the leaderboard through 36 holes via a dazzling round, which included six birdies and no bogeys.
It is the third time Westwood has led after two rounds at The Players Championship – in 2005 and 2010 – but he is yet to win.
The 47-year-old is a two-time PGA Tour champion, though his last success came in 2010.
Countryman Matthew Fitzpatrick (68) is a stroke off the pace, one shot ahead of Chris Kirk (65) and Sergio Garcia (72), who led after the opening round.
U.S. Open champion and Arnold Palmer Invitational winner DeChambeau posted a second-round 69 to be tied for fifth at six under.
World number one Dustin Johnson's second round in the 70s catapulted him up 22 positions into a tie for 36th, eight shots behind Westwood, while Jordan Spieth (74) is a stroke further back.
Xander Schauffele (74) was among the stars to miss the cut – the American's Tour-best streak of 23 consecutive made cuts coming to an end.