Damien McGrane heads the Irish challenge after the first round of the Portugal Masters in Vilamoura but the real story lay much further down the leaderboard where Peter Lawrie and Kevin Phelan are struggling in their bids to gain European Tour cards for next season.

With only the top 110 players on the Race to Dubai standings set to earn their playing rights for the new season after news week’s Hong Kong Open, both Lawrie (123rd) and Phelan (126th) realistically require top five finishes this week if they are to force way into the reckoning.

But with Belgium’s Nicolas Colsaerts and England’s Andy Sullivan topping the field on seven under, Phelan found himself in a tie for 47th on one under while Lawrie was three shots further off the pace and back in 98th place.

It was a mixed day for Paul Dunne in his third professional event, the Walker Cup star enjoying a brilliant opening morning before coming unstuck with a double bogey on the 18th (his ninth).

The Greystones golfer Dunne, who finished 19th in the Dunhill Links and 25th in the British Masters at Woburn last week, began his opening round in Vilamoura with an eagle on the 10th hole - his first - before following up with a birdie on the 11th, and another on the 14th, 15th and 17th.

After that double bogey Dunne dropped a further shot on the seventh leaving him three under par overall. Damien McGrane went one shot better thanks to two birdies and an eagle on the 17th.

Colsaerts continued his brilliant run of scoring in this event to claim a share of the lead.

Colsaerts fired a seven-under-par 64 at Oceanico Victoria Golf Club, the course where he narrowly missed a birdie putt on the final hole of his opening round 12 months ago to record the first ever 59 on the European Tour.

The 32-year-old went on to finish second behind France’s Alexander Levy in an event reduced to 36 holes due to bad weather, but is in pole position to go one better and secure his first win since 2012 after carding two eagles, four birdies and one bogey.

Sullivan carded eight birdies and one bogey to catch Colsaerts late in the day — which began with a 55-minute delay due to fog — with Thomas Pieters, Eduardo de la Riva, David Drysdale and Thomas Aiken all on six under.

Starting on the back nine, Colsaerts birdied four of his first six holes before a superb approach to the par-five 17th left the big-hitting Belgian just three feet for eagle. The world number 233 chipped in for another eagle on the fifth before an errant drive on the seventh cost him his only bogey of the day.

“It’s one of those courses where I feel comfortable,” Colsaerts, who is 22 under par for his last three rounds here, told Sky Sports 4. “My length is also a pretty big advantage.

“There are a couple of holes where I can take shortcuts and it does not really matter if I hit it on the fairway or in the rough, even though the rough is higher this year.

“I would rather come in with a pitching wedge from the rough than a six or seven iron from the fairway so it’s one of those courses where hitting it a long way is definitely an advantage.”

Sullivan, who has won twice on the European Tour this season, said: “I got off to a little bit of a scrappy start but made a good swing on the seventh and grew in confidence. I hit a lot of nice shots in the middle of the round and putted quite well on the late afternoon greens.”

Colsaert’s fellow Belgian Pieters, who won the Czech Masters and KLM Open in back-to-back appearances recently, was denied a share of the lead when he dropped his only shot of the day on the ninth, his final hole.

“My putting the last couple of weeks has been pretty off, so I’m happy that’s back,” Pieters said. “I feel comfortable and when my putting is going well, the confidence in the rest of my game is there.

“I would like to more consistent for sure, I had a couple of rough months in the summer, but my game is good and I feel like I can compete every week, which is very satisfying.”

Pre-tournament favourite Martin Kaymer was three under par after five holes, but eventually had to settle for an opening 70, while Denmark’s Anders Hansen carded a 68 in his last tournament before retiring.

“It’s been a long career,” said the 45-year-old, who won the PGA Championship at Wentworth in 2002 and 2007 and finished third in the US PGA in 2011. “

“I’ve enjoyed my time out here but I have a couple of business ventures going on at the moment and it’s tough to compete at this level and do other things, so I felt now was the right time to move on.”