World Invitational: Stephanie Meadow in the hunt after day one
Jordanstown's Stephanie Meadow is three shots off the top of the leaderboard after day one of the World Invitational at Galgorm Castle and Massereene.
Eleanor Givens leads the women's tournament on six under par with County Cavan's Leona Maguire five shots back following a round of 71.
In the men's competition, Craig Ross carded 64 to take a one-shot lead.
Last year's NI Open winner Calum Hill remains in contention after a four-under 66.
The highly-anticipated tournament received considerable interest in the build-up for its innovative approach - encompassing separate men's and women's events with equal prize money (£207,000) up for grabs in both.
Solheim Cup star Charley Hull is arguably the biggest name in an impressive women's field, but it was Givens who set the pace with four birdies on the front nine.
Hull looked set to finish the day near the top of the leaderboard after an eagle at the 16th brought her to two-under, before a triple bogey at 17 saw her finish the opening round tied for 27th on one-over.
Solheim Cup captain Catriona Matthew was a further shot back after shooting three bogeys and a birdie in her round of 74.
Home favourite Meadow began her round with back-to-back birdies, dropping just one shot at the seventh on her way to 70 while Maguire, in her first tournament in Ireland since turning professional, birdied the 16th to come in one under par.
"Overall it's a decent start," reflected Meadow.
"I was a little nervous on the first tee, more emotional than anything. I want to play well and give everybody a show who came to support me."
Hill seeking promotion as Ross leads
In the men's competition, which retains the European Challenge Tour status that predecessor the Northern Ireland Open had, Scotland's Ross made four straight birdies on the front nine to surge into the lead.
Two shots back is Ross's compatriot Hill, who will gain immediate promotion to the European Tour should he win this week, having already triumphed in Denmark and Austria this season.
Highly-rated Northern Irish prospect Tom McKibbin endured a difficult day finishing on three over, with Cormac Sharvin the best placed home golfer after his round of 68.
"It was playing tricky," said Sharvin.
"A lot trickier than I thought it was going to be so I'm pretty happy with two-under."