Paul Dunne surged to within a shot of the lead before play was suspended as Pádraig Harrington,  Seamus Power and Shane Lowry also came out firing in the last chance saloon for their Masters hopes in the Houston Open.

All four need a win to make it to August National and after Harrington and Power fired 67s to lie just two off the lead and Lowry birdied his last three holes for a 68, Dunne raced to six under through 14 holes before play was suspended for the day.

With tee-times delayed by two hours due to heavy rain, 33 players must return early on Friday to complete their opening rounds at the Golf Club of Houston.

They include Dunne, who birdied the third from 20 feet and the fifth from 10 feet before making an eagle three at the eighth, where he hit a 248 yard approach to 10 feet.

The Wicklow man then sank a 33-footer at the 12th and a nine footer at the 13th to move up to tie fifth on six-under behind clubhouse leaders Lucas Glover and Kevin Tway, who shot seven-under 65s in soft windless conditions early in the day.

Harrington was doubly pleased with his 67, which was his first round in the sixties and his first bogey-free effort in more than four months.

Dedicating his score to his mother Breda, he told Sky Sports: “I’d just like wish my mother a happy birthday today. It’s a decent birthday present for my mother today. 

“She’s at home and would have been worried about me, not missing the cut, but certainly not shooting a good score, so it’s a decent birthday present that.”

As Glover and Tway opened with seven-under 65s in low-scoring conditions on a course softened by heavy overnight rain to lead by a stroke in the clubhouse from Ryan Armour, Rickie Fowler, Julian Suri and Australian veteran Rod Pampling, Power followed his career-best share of fifth alongside Dunne in the Corales Puntacana Resort & Club Championship last Sunday with another good performance.

Like Harrington, he took advantage of soft conditions and birdied his last three holes to match Harrington, who desperately needs a positive result after missing the cut in five of his first six events this year.

“To get something going, especially at the end, is always nice,” said Power, who broke a bad run of four successive missed cuts in the Dominican Republic last weekend.

“I kind of lost my way and had to reset and figure out what I was doing with my swing. So last week was nice just to get a bit of confidence from being in contention and hitting good shots under pressure.”

He pointed to the seven-footer he made on the final green last Sunday as a sign he’s becoming more comfortable at the top level.

“Last year the chances are I might have missed it, thinking about what the money might mean, or what the points mean,” he said. “Now you realise it’s a long season, so just knock it in and worry about what all that stuff means later.

“You just get more comfortable watching other guys hit shots and say to yourself, ‘I am well able to play out here’. It's just a matter of putting it together.” 

Harrington (46) birdied the 10th, 12th and 15th to go out in three under and could have been a few shots better had a few long-range putts dropped in the middle of the round.

But he then made a 25 footer at the 454-yard fifth and only had to work hard for par at his 15th, where he hit a poor drive and missed the green before saving par from 17 feet.

“I haven’t been shooting too many good scores so I’m very pleased,” said Harrington, who tapped in from 18 inches for his fifth birdie at the par-five eighth.

“Bogey-free is always nice and to be honest, it was pretty easy today. I didn’t get myself in much trouble and it was stress-free. We had placing which covered everything and they pushed a few tees up. It wasn’t a tough test today. 

“For the first 14 holes I wasn’t out of position and had a lot of birdie chances. If it was my day I could have been three or four better. I struggled a little on the last four holes — it was my normal golf— but I liked what I saw.”

A week’s competitive practice in Florida with Lowry and former Shamrock Rovers football, now golfer, Stephen Grant looks to have paid off.

“I played a lot of golf and mentally I was definitely better,” Harrington said. “I see some good things and I know what I need to do, which is a nice place to be. I'm happy with where my swing is going. It’s more focus related than anything else.”

Like Harrington, Power also started on the back nine and followed a three-putt bogey at the 12th with a birdie at the par-three 14th before racing home in 31 for his 67.

The Munster man (31) made a 16 footer at the first, 13 footers at the fourth and seventh and a tap-in birdie at the par-five eighth before rattling in a 27 footer for a two at the ninth.

Lowry’s round was similar to Power’s as he started on the back nine, going out in one under thanks to an opening birdie at the 10th.

He then picked up another shot at the third and followed a bogey at the fifth with three closing birdies to share 10th with Phil Mickelson, Henrik Stenson and Jordan Spieth, who also finished with three birdies for a four-under 68 in his quest for confidence ahead of the Masters.

Spieth said. “I thought that four-under felt like a six-under to me, so that means good things are coming.”

Admitting the game has tested his patience recently, he added: “Absolutely. It’s been testing how I feel about myself more than anything — my self-confidence.

“I have been putting in a lot of good work on and off the course so it was an exciting day for me.

"I am talking like I shot eight or nine under but I have got to take one step forward to start climbing up the hill again.”

Mickelson went out in six under 30 but came home in 38 with eight pars and a double bogey five at the 14th on his card.

American Sam Ryder was eight under with three holes to play with Beau Hossler seven under after 16.