John McHenry, the specialist we had overlooked, claimed a share of the halfway lead in the Murphy's Irish Open at Druids Glen yesterday. However, the 34year-old Corkman's elevated status was largely due to a dramatic slide by an injured Colin Montgomerie, who carded a 74, his highest score at this venue.

It was only when McHenry had carded a fine 68 for a halfway total of 138 - four under par - that memories of his Irish Open exploits at Mount Juliet came flooding back. In 1993, when Nick Faldo completed a record third successive triumph, McHenry was joint leader with Jose-Maria Olazabal after 54 holes.

He slipped to a closing 79 and a share of 14th place on that occasion, but was back the following year to finish as leading Irishman, in a share of 15th place behind Bernhard Langer. "I hope I've learned from Mount Juliet, but I'm now thinking of Druids Glen," he said. "There are very positive elements here."

When McHenry looked destined to have Montgomerie as his third round partner today, the Scot took an unexpected tumble from the top of the leaderboard. At one stage of his outward journey he was eight-under-par, but a back nine of 40 saw him drop into a share of fourth place, albeit only one stroke off the lead.

The Scot later explained that he was injured while signing autographs after Thursday's round. "I didn't look when I was going and I tripped up over a stone and twisted my ankle badly," he said. It also transpired that he had torn a ligament in his right foot which had to be strapped before yesterday's round.

He added: "The last fairway I hit was the 10th and it became very difficult coming in. So I'm now going down to the 3M bus (the mobile physiotherapy unit which travels with the tour) for further treatment.

"I took several painkillers on the way round but they had worn off by the time I reached the 10th. Either way, I'm one stroke behind and that's not a bad position to be in. In my own eyes I'm still favourite."

McHenry and the unknown American, Craig Hainline, became highly-improbable joint leaders, only to be joined late in the day by Tony Johnstone, the 1992 Volvo PGA champion. Despite all his characteristic fidgeting and twitching over the ball, the Zimbabwean had a 67 and claimed the distinction of a birdie at the notorious 13th for a second successive day.

Hainline, competing in the Irish Open for the first time, is a 28-year-old American from Kansas who gained his card on the European Tour last November. "As an amateur, I represented my college, Oklahoma State, where Bob May, Carl Suneson and Philip Walton also played," he said. "And we're all here this week."

Walton's presence, however, lasted only two rounds. In fact only five Irish players from an entry of 27 survived the halfway cut of 147 - five over par. And among the survivors was David Higgins, who advanced impressively to the weekend after a second-round 69 that contained five birdies.

But scoring of that quality was rare. In the first round only 24 competitors broke par from a field of 156. By this stage the parbreakers are down to 11. A relentless challenge has taken its toll.