Padraig Harrington will lead the Irish challenge into the final day of the Dubai Duty Free Irish Open.
The 2007 winner had a one-under par round of 71 at Portstewart today, which moved him to eight-under.
Shane Lowry, Paul Dunne and Michael Hoey are all six-under after three rounds while Gavin Moynihan closed on five-under.
Having persuaded Jon Rahm to enter his event, Rory McIlroy could end the week by handing him the trophy after the Spanish star surged into a share of the lead.
Rahm, who outscored playing partner and defending champion McIlroy by 13 shots over the first two days, carded a third round of 67 to finish 17 under par, a total matched by American Daniel Im.
The world number 11 took advantage of glorious conditions at Portstewart Golf Club to fire six birdies and a solitary bogey, four of the birdies coming in succession from the 11th.
Since turning professional just over a year ago, Rahm has claimed his first PGA Tour title and racked up a string of impressive performances, including finishing third and second in his first two World Golf Championship events.
And the 22-year-old now has the chance of following in the footsteps of fellow Spaniards Seve Ballesteros, Jose Maria Olazabal and Sergio Garcia in winning the Irish Open.
"It could be a very special day tomorrow," said Rahm, who described his adventurous birdie on the par-five 14th as a "Seve birdie."
"This tournament has a good Spanish history and it would be great to join that.
"I've never led going into the final round so I am a little inexperienced in that sense, but I know what I did at Torrey Pines [where he won the Farmers Insurance Open], both good and bad. Hopefully I won't need two eagles in the last five holes again to win tomorrow.
"I have exceeded my expectations massively. My putting and short game has never been my best ally on links courses, but this week has been the opposite. I'm not used to making this many putts and it feels great."
Rahm, who is playing just his second regular European Tour event and finished 10th in the HNA Open de France last week, added: "Before I won at Torrey Pines this was not a possibility.
"The only chance to come and play would be to be invited. Winning that tournament meant I was able to come here and pick and choose events. So to achieve a goal that was not even in my mind at the start of the year would be very special."