(Photo credit: Raymond Carlin III-Imagn Images)

Brianna Do birdied the 18th hole to forge a tie atop the leaderboard at 6-under-par 66 with fellow American Melanie Green after the opening round of the Riviera Maya Open on Thursday in Playa del Carmen, Mexico.

Green, an LPGA rookie, sank a hole-in-one amid a busy first nine and went birdie-bogey on her last two holes to settle at 6 under.

The co-leaders are one shot ahead of Spain's Carlota Ciganda, alone in third at 5-under 67 after mixing seven birdies with a pair of bogeys.

Do started strong with four birdies in the first five holes of her round at El Camaleon Golf Course. After closing the front nine with her lone bogey, she responded with consecutive birdies on Nos. 11 and 12 as part of a 3-under back nine.

On a windy day, Do credited a critical round she recently played in heavy wind for helping keep her calm Thursday.

'I actually had my U.S. Open qualifier, I don't know, like two weeks ago or a week ago, and it was very windy, so it kind of helped me prepare myself for this week mentally,' Do said.

'(My strong start) kind of gave me a good start and a good cushion to kind of play aggressive the rest of the round.'

Green, who began on the back nine, was 6 under through nine holes (one ace, five birdies, one bogey). After birdies at Nos. 17 and 18, Green briefly moved to 7 under with a birdie at the par-3 8th but bogeyed the finishing par-4.

The highlight of Green's round came at the par-3 15th hole. However, she didn't see the ball go in and didn't believe her caddie when he informed her.

'I'm like, 'Shane, that's not nice. It's not in the hole. That's not nice,'' Green recalled. 'I walk up there and all I could see was the cross. I was so excited. Yeah, thought I just went way left. But whatever. Good bounce.

'I can't say that (a hole-in-one) was a goal of mine this year, but always fun to have. It's more fun when you can see it go in, but that's OK.'

Do, 36, debuted on the tour in 2013 while Green, 24, debuted this season. But both are searching for their first LPGA victories.

In fact, Do's only career top-10 came last year in the inaugural Riviera Maya Open, tying for ninth at 3 under.

'Having a good week here last year brought good vibes coming back, so I was excited to be back here and try and better how I played last year,' Do said.

Nelly Korda, who reclaimed the No. 1 spot in the Rolex Women's World Golf rankings with last week's victory at the Chevron Championship, is one of six players tied for fourth at 4 under. Also in that group are Japan's Erika Hara, Mexico's Gaby Lopez, Japan's Cocona Sakurai, South Korea's Soo Bin Joo and Thailand's Suvichaya Vinijchaitham.

Chizzy Iwai of Japan, who won the inaugural event last season, is tied for 85th at 3-over 75, weighed down by a double bogey at the par-3 8th.

--Field Level Media