There are three Irish players inside the top ten at the Houston Open - each of them giving themselves a chance of qualifying for next week's US Masters.

American Sam Ryder is the clubhouse leader in the final tournament ahead of the first golf major of 2018, but heavy rain meant he along with several others didn't get to complete his opening round.

Ryder is eight under after 15 holes, one ahead of Lucas Glover, Kevin Tway, Beau Hossier, with a further stroke in hand over Rickie Fowler, who all played 18 holes.

Leading the Irish charge in tied fifth is Paul Dunne on minus six, while Padraig Harrington and Seamus Power are both on minus five after shooting 67.

Ireland's fourth representative in the tournament isn't doing too badly either - Shane Lowry is tied 26th after his first round 68 left him on four under, four off the pacesetter in a crowded leaderboard.

All of the Irish have to win the tournament to qualify for the Masters next week - no other results will do.

The opening day in Texas was delayed by two hours due to more than two inches of raining falling overnight and poor light meant the later starters weren't able to complete their opening rounds

Harrington is in contention

Phil Mickelson - 43-time PGA Tour winner - shot a 30 on the front nine to start his week, helped by an approach shot within five feet on the par five fourth.

But the form did not continue into the back nine where he double bogeyed the par three 14th and sits tied for 26th on four-under along with Justin Rose and Lowry.

Defending champion Russell Henley carded a 69 to sit tied for 48th.

Harrington, who has twice finished fifth in the Masters but has not played competitively at Augusta National since  2015, carded five birdies in a bogey-free 67 to finish a shot ahead of Henrik Stenson and Jordan Spieth.

Spieth, who won his first major at Augusta in 2015 and blew a five-shot lead with nine holes to play in the defence of his title, finished his round in style with birdies on his last three holes.