Pádraig Harrington's putting woes caught up with him just when it looked as if he'd turned the corner in the Honda Classic.

The Dubliner missed a few "shorties" early in the day, then holed as series of clutch putts on Sunday afternoon to go into the final round just three shots behind new leader Ian Poulter.

But just as quickly as he had moved right into the mix again, he missed twice inside five feet and dropped three shots in six holes to slip four shots off the pace with 11 holes of the final round remaining. 

In short, his hopes of a first PGA Tour win for six years, six months and 21 days are clearly on life support.

Still, as he told Golfweek's Alex Miceli, he's optimistic: 

“The great thing about it, as bad a day as I’ve had, I have a chance tomorrow. I’m delighted to see the delay. For me, it’s the best possible thing that could have happened.... it certainly wasn’t great day for me... Hopefully tomorrow it will go my way, but it needs to at this stage. That’s the one problem I left myself. When I was 9 under par, it didn’t need to go my way. Now, it does. . . . It can be done.”

Poulter was still there at the head of affairs after another afternoon of car crash golf in what has become one of the PGA Tour's most entertaining events in recent years.

The English star ended his day by making a brave, comeback birdie from about three feet at the par-three seventh, easing the pain of a spectacular shank into the lake that led to a double bogey five at the par-three fifth and a pull-hook into the water that cost him a bogey at the sixth.

At seven under par, two over for the final round, Poulter was tied for the lead with compatriot Paul Casey, who managed to play nine holes of the final round in an immaculate, four under 31 before play was suspended due to darkness.

US Ryder Cup star Patrick Reed is lurking just a shot off the lead on six under after a careless bogey at the seventh.

The bad news for Harrington is that while he is "only" four behind with 11 holes play, his putting under pressure looks highly unreliable and he's tied for ninth with six players between him and the two Englishmen: the dogged Reed (7 holes), Daniel Berger (11 holes), Jeff Overton (10), Phil Mickelson (8 holes, facing a 10 footer for par on 9), Brendan Steele (8) and Russell Knox (8).

Harrington walked off the seventh green with a wry smile on his face having been forced to hole a five and a half footer for par after leaving his 30-foot birdie effort short.

The irony of the moment was clearly not lost on him after he had severely dented his chances of challenging for a first PGA Tour win for nearly seven years with some big mistakes from close range.

The Dubliner had struggled with the blade early in the day, missing twice from four feet as he played the first 10 holes of his third round in three over before rallying on the way home.

Birdies at the 11th and 14th and a fine par save at the 18th, where he got up and down from 130 yards having sliced his 270 yard approach into the lake, added up to a third round 71 that left Harrington tied for second with Reed on six under, three strokes behind an imperious Poulter, who had posted an immaculate 66 in his quest for a first strokeplay win in the United States.

With just under two hours of daylight remaining, the leaders headed back out again and it was Reed who found himself tied for the lead when he birdied the fifth from off the green as Poulter doubled following that shank.

Harrington had slipped four behind by three-putting the fourth, misreading is approach putt before wafting a four footer off the bottom lip.

The Dubliner walked off the fifth green just three behind Reed and Poulter but he made a double bogey six at the tough sixth when he carved his tee shot miles right and then took four to get up and down from 65 yards, pitching through he green and then missing a five footer for bogey.

Jack Nicklaus, who is one of the main drivers of the tournament's charity focus, watched Harrington hit into the water on the 18th at the end of his third round and told Sky Sports he spotted tension in the three time major winner's take away on his approach, which is only to be expected after such a prolonged absence from the top of the leaderboard on the PGA Tour

"I haven't watched a lot of Pádraig lately but on the 18th hole I watched him hit his second shot and I watched his takeaway and watched how he left his body there. It's just tension. He started his hands away and got himself out of rhythm by getting the hands back there and all of a sudden you've got a situation where you are going to hit it left to right. The third shot he hit [Harrington's fourth after a penalty drop], the swing was absolutely pitch perfect. I hope he doesn't make that mistake again because I like Pádraig. He's a nice player and a nice young man."

Harrington may yet drag himself back into the mix but it will take birdies and eagles now.

As for Poulter, who has yet to win a strokeplay event in the US, he was impressive all day until his shank, carding four birdies in an immaculate 66 to top the leaderboard on nine under after the third round.

He played the first nine in flawless fashion, picking up shots at the first, sixth and seventh to get to eight under. But Harrington was far from confident.

He missed a four footer for par at the second having donned the waterproofs to play his approach from the hazard on the left, missed a chance from eight feet at the sixth and then three putted the seventh from 26 feet, missing another four footer.

Back to five under par, Harrington missed the green and six footer for par at the 10th to trail Poulter by four shots.

The Englishman was in superb form but Harrington did not go away and made a superb three at the tough 11th, hitting a perfect tee shot and a lovely second from 190 yards to just nine feet.

He rolled in the putt, saved par from five feet at the 12th and then hit a wedge to four feet at the 13th and holed that too to get back to one over for the day.

Just three shots off the lead, Harrington had chances at the 14th and 15th, the former coming thanks to a fine approach to 11 feet from a fairway bunker on the left.

With Reed struggling and Steele dropping shots at the 14th and 15th, Harrington was back in solo second and chasing Poulter.

Casey finished the third round tied for fifth, six strokes behind Poulter. Two hours later he was tied for the lead with his former Ryder Cup team mate, setting up what should be a fascinating Monday morning shootout.