A remarkable turnaround in fortunes that culminated in a 66 has left Pádraig Harrington in the clubhouse lead at the Barclays Singapore Open, though out on the course Chapchai Nirat of Thailand was four shots better off through 12 holes of this third round.

Darkness brought third round play to an early end today but not before Dubliner Harrington improved dramatically on his first two rounds to go into the clubhouse on five-under-par.

He was joined on that score by world number three Phil Mickelson (four under through 14), Ernie Els (one over through 11), Rory McIlroy (one under through 11) and Jeev Milkha Singh (four under through 14).

Although there were no stoppages today, long weather delays on the first two days meant that third round play only began in the afternoon with only 27 of the 72 players who made the cut able to complete their rounds.

The 25-year-old Nirat from Bangkok began the third round on four under, two strokes adrift of co-leaders Simon Dyson and Els.

He made birdies on the third and fourth but was still a shot adrift of Dyson and Singapore's Lam Chih Bing after nine holes at Sentosa Golf Club's Serapong course.

But the Thai nailed a 10-foot birdie at the 10th to make it a three-way tie for the lead before jumping two shots in front with his eagle on the 11th when he chipped in with a pitching wedge from 118 yards.

Chapchai went on to par the 12th when play was halted, leaving him on five under for the day and nine under overall.

Dyson, Lam and Thomas Bjorn were tied for second on seven under at the time of the stoppage.

Dyson was six under at the start of play and picked up a shot with a birdie on the fourth while parring all of the other 10 holes he played.

"My game feels good. I'm playing all right," said the Englishman, who is feeling the effects of fatigue after playing at the Hassan II Golf Trophy in Morocco last week.

"I normally like to attack stuff but I'm holding back a bit as I'm tired.

"I'm right in it though. Bogey free yesterday and bogey free today which is a good thing.

"I'm playing a bit conservative but hopefully I'll get a good night's sleep and come out blazing tomorrow."

Lam was tied with Chapchai on four under at the start of the round and made birdies on the second and fourth before holing his third of the day with a four-footer on the ninth. He was facing a 15-foot putt for par on the 12th when play ended.