Graeme McDowell and Rory McIlroy launched a Friday afternoon McAttack to join the Irish charge and set up a Bank Holiday mega-party in Killarney
With Darren Clarke and Padraig Harrington missing the cut, a damp squib weekend was on the cards if the other major winners failed to ignite.
But McIlroy made a late charge to shoot 67 and G-Mac weighed in with a sizzling 66 to get within six shots of leader Marcel Siem (66) on four under par.
The Ryder Cup duo aren’t even the leading Irishmen with amateur ace Paul Cutler, Ulster star Michael Hoey and pals Peter Lawrie and Damien McGrane all just four off the pace on six under.
Hoping to fire up the home crowd, McDowell said: “Of course we are disappointed that Pádraig and Darren are not here but we’ll try and make a great weekend of it and see if we can get a home winner.
“It would have been great to get us all up there in contention but the crowds have been fantastic. They just came out in the hundreds of thousands and really given us great ovations coming on to the greens.
“The event has got exactly what it needs. It’s got some sunshine, a great venue and massive crowds.”
McDowell celebrates his 32nd birthday today and with a best finish of 11th in nine previous appearances he wants to give himself an Irish Open gift.
After firing six birdies, he said: “My record here is not stellar, but very happy to go out and play the way I did today, and I’ll be looking forward to a good day tomorrow.
“It’s my birthday so I’ll be looking at my 32nd year, and it will be nice to go out there and shoot a little 64 or 65, be a nice birthday present.”
McIlroy got his driving back on track and thrilled the 20,000 strong crowd as he made a move with three birdies on the trot from the 14th.
Ready to make a weekend charge for the title, Rory said: “It’s a very bunched leaderboard. If I can get off to a good start tomorrow, get myself to six or seven under for the tournament early, I’m right back in it.
“There are 36 holes to go and five shots over 36 holes isn’t really that much. And I saw enough positive signs out there today to put me in a good frame of mind going into the weekend.
“If I shoot two rounds in the 60s I’ll be in with a great shout on Sunday.”
The big guns were overshadowed by the lesser lights for once with amateur sensation Cutler joined near the top of the leaderboard by Lawrie, McGrane and Hoey.
Both McGrane and Hoey have changed putters this week to try can change their luck on the greens and it has certainly worked.
McGrane fired a 67 thanks to a run of four birdies on the trot from the seventh that included a 40 foot bomb on the eighth and an outrageous chip-in at the next.
Asked his secret, McGrane joked: “I don’t know, maybe Holy Water was falling on my head. I holed a long putt on No 8, out of the blue I must admit.
“Then I chipped-in on nine, birdied the par three, No 10, so that was a good roll there. All of a sudden I went from treading water to going forward fast.”
Lawrie was just two under for the tournament with six to play but the putter he rescued from his garage heated up and he birdied the 13th, 14th, 16th and 18th to move right into contention.
Lawrie said: “I looked at the leaderboard and said to myself, if I can get to five under standing on the 18th tee, it would be a good goal.
“I holed nice putt on 13, on 14 as well and birdied 16. So all of a sudden I was five under playing the last.
“I am always hitting driver off the last and leaving myself a short iron to the green and lo and behold I made another birdie. So I am really happy.
“It’s an old putter I took out of the shed and changed the grip and it’s been working nicely.”
Nine Irishmen made the one under par cut with Simon Thornton (72) on two under and club professional John Kelly brilliantly making it on the mark after a super 68.
The St Margaret’s man was three over for the tournament after a bogey at the first but played the remaining holes in four under with birdies at the second, fifth, ninth, 14th and 16th cancelling out a bogey at the 17th.
Siem put on a late-late show to grab the lead but the former World Cup winner, 31, has a huge international contingent and a posse of Irishmen breathing down his neck.
Chasing his first win for seven years, he eagled the 16th and then birdied the 17th to snatch top spot thanks to a five under 66.
He tops the leaderboard by a shot on 10 under par from Dane Soren Hansen (66) and overnight leader Jeev Mlkha Singh (70).
But there are 34 players within just six shots of his lead with Spaniard Ignacio Garrido two behind after a 65 and the Irish quartet of amateur Paul Cutler, McGrane, Hoey and Lawrie just four behind in joint 11th.
McIlroy and McDowell are only six behind and sure to set the crowd alight after Darren Clarke and Padraig Harrington missed the cut.
With just nine shots covering 71 players, the race for the €250,000 prize is wide open.
Defending champion Ross Fisher hit a 68 to finish just three off the pace in a five-man tie for fifth with fellow Englishmen Simon Wakefield, Oliver Wilson and Simon Dyson, Aussie left-hander Richard Green and Frenchman Raphael Jacquelin.
Singh led by two after an opening 63 that matched the lowest round of his career and despite a wild opening drive into the stones beside Lough Leane, he settled down to fire a 70 that gave him the clubhouse lead for much of the day.
He was joined on nine under by former Ryder Cup star Hansen who had six birdies in his 66 before Siem caught fire late in the day.
A World Cup winner with Bernhard Langer in 2006, the fiery German could earn the right to join Martin Kaymer in China later this year.
Vctory in Kerry would help the world No 295 overtake Alex Cjeka and earn another World Cup start, but he’s not getting ahead of himself.
Famous for his erratic temperament, he said: “There is a another two rounds, it is only halftime. I just want to stay calm and see what happens.”
7.50 Murray; 7.59 Webster, Coles; 8.08 Echenique, Kelly; 8.17 Lafeber, Luiten; 8.26 Sjoholm, Ferrie; 8.35 Drysdale, Fisher; 8.44 Whiteford, Goya; 8.53 Saltman, Dinwiddie; 9.07 Horne, Davies; 9.16 Fritsch, Fraser; 9.25 Tullo, Floren; 9.34 Thornton, Derksen; 9.43 Kapur, Cañizares; 9.52 Kaleka, Van Zyl; 10.01 Dixon, Cevaer; 10.10 Foster, Parry; 10.19 Khan, Moriarty; 10.28 Fasth, Bland; 10.42 Morrison, Haines; 10.51 Brown, Wall; 11.0 Wattel, McDowell; 11.09 McIlroy, Howell; 11.18 Olesen, Aguilar; 11.27 Donaldson, Brier; 11.36 Gallacher, Lane; 11.50 Boyd, Ramsay; 11.59 Gagli, Nilsson; 12.08 Wiesberger, Hoey; 12.17 Lemke, Lawrie; 12.26 Horsey, Del Moral; 12.35 McGrane, Cutler (am); 12.44 Wilson, Green; 12.58 Dyson, Fisher; 13.07 Jacquelin, Wakefield; 13.16 Garrido, Hansen; 13.25 Singh, Siem.