Just 23 days after he crashed out of the US Open with a second round 82 - his second worst score ever in a major - Montgomerie had charged to the top of the leaderboard with a closing 65 across the River Liffey from where he celebrated Ryder Cup triumph last September.

Swede Niclas Fasth was one behind with only the par three 18th to come when the second interruption came because of yet another approaching thunderstorm.

On the last two holes - both par threes - Montgomerie was perilously close to going in the water, but saved par each time. Fasth could have levelled with an eight-foot putt on the 202-yard 17th, but it dribbled wide.

Montgomerie was 11 under, Fasth 10 under and two other players were not quite out of it, although Swede Peter Hanson had to birdie the last two holes to tie and Dane Soren Hansen needed birdies on the last three.

There was also a slight chance that France's Gregory Havret would force a play-off. Playing with Fasth he had to hole-in-one on the last - and there had already been aces by Hanson and Finn Mikko Ilonen there during the week.