Rory McIlroy hailed a 'big improvement' in his putting after a superb 65 lifted him into contention for a third WGC title in the Cadillac Championship at Doral.
McIlroy had finished third, sixth and 20th in his first three events of 2016 before a missed cut in the Honda Classic last week prompted him to switch to a ‘crosshanded’ putting method he last used in 2008.
The 26-year-old needed 33 putts in his opening 71 but just 25 on Friday in carding eight birdies and one bogey to finish eight under par alongside defending champion Dustin Johnson, two behind former world number one Adam Scott.
Offaly man Shane Lowry carded a one-over-par 73 to finish on level par heading into the weekend, 10 shots off Scott.
McIlroy, who single-putted nine of the first 12 greens, said: "I felt like I struck the ball well yesterday, I just did not have the pace on the greens.
“That's to be expected when you go to a new grip and are thinking more about technique than speed and feel.
"I did a bit of work on the putting green on Thursday night and it paid off on Friday."
The County Down man now has his stronger right hand at the top of the putter grip instead of his usual left.
After a birdie on the first was cancelled out by a bogey on the second, McIlroy birdied four holes in succession from the fifth to reach the turn in 32, before saving par from seven and nine feet on the tenth and eleventh respectively.
The world number three then birdied the 12th, 15th and 18th to keep Scott firmly in his sights, the Australian carding a 66 in pursuit of back-to-back wins following his victory in the Honda Classic on Sunday.
Speaking about his birdie from 19 feet on the last, McIlroy added: "I saw Adam had got to ten under so I didn’t want to be too far behind going into the weekend.
“It's great to see putts like that go in. Those are the putts I have not been holing over the last few months.
"When you see putts go in you do get confidence from that. As the days go by the more comfortable this will become and the more I can think about feel and picking the right line instead of where my hands are on the grip.
"Today I saw a big improvement so I'm very happy."
With Phil Mickelson finding water off the tee on the 15th to double bogey and Scott (above) dropping a shot on the 14th, McIlroy's seventh birdie of the day on the 15th briefly took him into a share of the lead.
However, in the group behind, Scott also birdied the 15th and then drove the green on the short 16th to set up another to move to nine under, two ahead of McIlroy, Willett and defending champion Dustin Johnson.
Scott was equally pleased after carding eight birdies and two bogeys in his 66, the former Masters champion responding to a dropped shot on the 14th with a hat-trick of birdies.
"I got off to a good start again and that's been the key for me the last few weeks," he said. "Then maybe the wind lay down a little on the back nine and allowed me to have the chance for a few more and I hit some good shots and took advantage."
Johnson carded eight birdies in a flawless 64, the lowest score of the week so far, to join McIlroy on eight under, with Danny Willett a shot behind after adding a 69 to his opening 68.
"I'm really happy," Willett said. "The wind was in a different direction so there were a lot of different shots you had to play. Fortunately the putter is behaving itself nicely and you would take sub-70 round this course four times."
Paul Casey and Phil Mickelson were three shots further adrift.