It effectively ended his hopes of winning the Smurfit European Open.
He now stands two over for the tournament after yesterday's 76 leaving Paul McGinley, currently in 6th place, easily best of the seven home survivors on three under par and six behind the highly impressive leader, US Open champion Retief Goosen.
Next best is Peter Lawrie, the 2003 Rookie of the Year, with two even par rounds of 72. Also through are Gary Murphy (three over), Darren Clarke and John Dwyer, the club professional at Ashbourne, four over, and Neil Manchip, the teaching professional at Royal Dublin on the cut mark of five over.
Harrington was not alone in finishing poorly. When Graeme McDowell birdied the short 12th, he was back to one over for the championship. After a par at 13, he proceeded to go bogey, bogey, double bogey, bogey and quintuple bogey at the 18th where he was three times in the water.
There were many disasters, but McDowell was one of only two players to run up double figures at any hole. His 79 left the Italian Open champion and Ryder Cup team challenger on 11 over and his quintuple at the last and that of Thomas Levet meant that every figure from one (the Spaniard Jose Manuel Lara aced the 11th) to 10 appeared on the scoreboard.
McGinley had the best seat in the house yesterday as Goosen's partner. In spite of shooting a high commendable one under 71, the Irishman was outscored five shots by the South African and was deeply impressed.
"I had two birdies and one bogey so I've got to be happy," he said. "But Goosen is on fire. He's probably the best player in the world at the moment. We're lucky to have him playing in the European Open. It adds to the tournament to have the US Open champion in the field. I hope he's not making it into a one-man tournament but the way he's playing, he's going to be difficult to beat.
"It's good to play alongside him and see how placid he is on the golf course just like he was at the US Open. "But I must concentrate on my own game. I'm playing the golf course, I'm not playing Retief Goosen. I've made that mistake before, trying to play people instead of the golf course, and you take your eye off the ball. I'm sort of going along with him rather than playing against him. I can't complain about the course. I'd say they are the best putting surfaces I've ever played on in the European Tour.
"I love playing in the wind. It's not moving the ball on the greens. It's a real test of golf."
Harrington, of course, spoiled everything with that dismal finish when he found water off the 16th and 18th tees and in between three putted from the edge of the short 17th. He insisted that he hit the ball well but he's now only making up the numbers for the weekend and the world number eight remains without a tournament victory since the Hong Kong Open last December. Having been out on the course at the same time as Lee Westwood, he reckoned that the Englishman's 69 possibly represented an even more impressive performance than the 66 of Goosen earlier in the day. As for Darren Clarke, things simply don't get any better. "If I had three putted the 18th to miss the cut, I wouldn't have been in the slightest disappointed," he groaned after his even par round of 72 at least meant that he avoided a missed cut for his third successive tournament.
I have rarely seen the man so despondent and this is a little difficult to comprehend given that a 72 in yesterday's conditions and on such a difficult course was by no means a poor performance. "The course was frustrating," he related, "because I couldn't get around it." He went with the belly putter for the second successive day but later declared that "it has its last outing."
Peter Lawrie is tied 18th and poised for a handsome cheque having missed the cut in each of his two previous outings.
: Qualifiers, 141 Paul McGinley. 144, Peter Lawrie. 146, Padraig Harrington. 147, Gary Murphy. 148, Darren Clarke and John Dwyer. 149, Neil Manchip. Non qualifiers: 152, David Higgins. 153, Stephen Browne. 154, Damien McGrane., 155, Graeme McDowell. 157, Leslie Walker. 160, Brendan McGovern.