David Howell hit a stunning third round of 64 to share the lead of the Irish Open at Killarney.
The 36-year-old last won a tournament in 2006 but will go into the final round level with Richard Green and Simon Dyson on 11 under par.
The Englishman started the day on four under but hit five birdies in six holes on the back nine.
Playing partner Rory McIlroy had a disappointing day as he carded a round of 72 to fall eight shots back.
Green and Dyson both scored 67 to move level with Howell at the top, while overnight leader German Marcel Siem dropped two shots on the 18th to end on eight under.
Howell - who has twice won the Ryder Cup with Europe - is currently ranked 282 in the world but was inspired by the crowds following US Open winner McIlroy.
He was ranked ninth in the world when he had his last win at Wentworth five years ago and showed impressive composure as he ignored the heavy rain to complete the back nine in 31 to complete his charge.
He joked: "I'm flying now - I must be one of the hottest players in the world.
"I've not been in the best of form, so I was intrigued how I was going to be playing with Rory. He's the star of world golf.
"While Rory was doing miraculous things at the US Open, I was absolutely shocking. We couldn't have had more polar opposite weeks.
"But there were no nerves and I think I was inspired by the atmosphere. The crowds were amazing."
McIlroy made a nightmare start when he double-bogeyed the opening hole and then dropped another shot on the short third.
McIlroy said: "It was not a great start, but I got it together at the end and one over is not too bad considering how I played at the start.
"At this tournament you're trying so hard to play well for not just yourself, but for everyone else. Sometimes you can just find yourself trying a little too hard and pushing a bit too much."
Fellow Northern Irishman Graeme McDowell, on his 32nd birthday, started with a birdie putt of nearly 20 feet but eventually matched McIlroy's score to also move to three under.
Peter Lawrie moved to seven under while Michael Hoey ended level with amateur Paul Cutler on six under.