COLIN MONTGOMERIE is racing certainty to be crowned European number one for a fourth successive year in Berlin this weekend. But his celebration party could be seriously spoiled by the trio of Irish golfers who yesterday unleashed a whirlwind assault on the Linde German Masters at the Motzener See club.

Montgomerie barely had time to celebrate a second round 67 for 137, which put him seven shots ahead of his departing chief rival - Ian Woosnam, before he was overrun by a tide of birdies from the men who will be challenging Scotland's hold on the Alfred Dunhill Cup at St Andrews next week.

Darren Clarke was the inspiration with a sizzling 64, but Paul McGinley and Padraig Harrington both shot 67 to put the squad a cumulative 30 under par at the halfway mark.

The day ended with Austrian Open champion McGinley holding a one stroke lead, at 11 under, over Clarke and England's Paul Eales. Harrington shares fourth place on 135 with South African Ernie Els, England's Paul Broadhurst, Welshman Mark Mouland, and New Zealander Michael Campbell.

The rampant Irish equally shared 18 birdies, and Clarke added an eagle three at the second in his best putting round of the season. He used his blade only 27 times, and though Broadhurst stole some of his thunder with a matching 64, there was no denying the massive boost to Irish golf prestige, despite the departure of Ryder Cup man Philip Walton.

"We need to get our bets on early for St Andrews," exclaimed a jubilant Harrington after almost scooping the hole in one prize of a £59,000 car at the 17th where his eight iron tee shot hit the flag.

He got a further boost when Raymond Russell, one of his chief rivals for the Rookie of the Year award, had five three putts in a 78 and followed Woosnam, and British Open champion Tom Lehman out of the tournament.

Woosnam had a 75 for level par, one outside the qualifying mark, and remarked: "It's all over now, and I can go home." He ended his season long struggle with Montgomerie disconsolate with his putting, and struggling to swing freely because of his aching back.

Even if Woosnam returns to win the Volvo Masters' top prize of £150,000 at the end of the month, Montgomerie has only to finish in the top 40 tomorrow night to be in an unassailable position.

"Technically it is not over yet," he said, "but it should not be beyond me to finish in the top 40. Now I can relax, enjoy the weekend, and hit the putts a bit harder. I have been playing two tournaments each week, one against Ian Woosnam, and the other against the rest. Now I can concentrate on winning this title, that is my goal."

The Irish, and also old rival Ernie Els who had 67, are determined to make it difficult for the Scot to add this crown to his victories in Dubai, Ireland, and Switzerland. And Montgomerie knows he cannot afford more errors like the double bogey he took at the 16th on the first day and the seven he had at the long fifth yesterday.

A hacker's double, in which he skulled a bunker recovery and duffed a chip, was a shock after four birdies and an eagle in his first 11 holes. But Montgomerie proved his resilience by finishing with two birdies, and it will be a major surprise if he is not in the shake out with his Celtic rivals for the top prize of £108,330 tomorrow.

McGinley said: "It is just coincidence that the three of us are playing so well at the same time. My game is solid, Padraig's has been all year, and Darren is coming back to form with the putter. We are all looking forward to next week."

Clarke, who breezed out in 31, and collected his sixth birdie at the 13th, commented: "Since I left Bill Ferguson and went to Peter Cowen a month ago, my game has improved significantly." He has also gained better balance when putting by widening his stance.

Walton had every prospect of joining the spree after his opening 68, but he dropped three strokes in his first five holes, and was always struggling in the course of a 76 for 144. Even so, he looked likely to survive until he called a penalty stroke upon himself on the 16th green when his ball moved after he had started his backstroke with his long putter. A double bogey resulted, and though he birdied the last, it was no more than a defiant gesture from a tired looking golfer.

Ronan Rafferty went in the opposite direction by scoring 68 for 141, securing his survival by having birdies at the first four inward holes.