The 18-footer for birdie on the final hole slid by on the left, another chance lost on a day filled with missed opportunities. Rory McIlroy walked off the green and gave his putter a gentle spank, as if to punish it for letting him down when he needed it most.

His even-par 72 wasn't awful by any means and might have been a score he would have settled for in another Masters. But on a day when 32 players broke par, the No. 2 player in the world wasn't exactly pleased.

He got a kiss and hug from girlfriend Caroline Wozniacki after signing his scorecard, but any overtime work on the putting green would have to wait. It was getting dark and, just as McIlroy was beginning to talk about what went wrong, the weather sirens sounded and he was hustled inside the Augusta National clubhouse.

Athlete girlfriends steal spotlight

Think of it as power couples instead of Fred Couples.

Some of the talk Thursday at the Masters wasn't just about what was happening on the tees and greens, but who was outside the ropes looking in. The No. 1 and No. 2-ranked players in the world, Tiger Woods and Rory McIlroy, had entourages that included girlfriends with some pedigree of their own.

For Woods it was Lindsey Vonn, the Olympic ski champion and now his very public companion. She watched from the clubhouse lawn as Woods teed off on No. 1, and lingered around to see him after he came off the 18th green.

In between, she drew a crowd of photographers who gathered around her while Woods played the ninth hole.

Woods and Vonn acknowledged their relationship last month in posts on social media, complete with studio pictures of the couple. The last time Woods won the Masters, he was married to Elin Nordegren. They divorced in 2010 after Woods admitted numerous marital indiscretions.

Caroline Wozniacki, once the No. 1 tennis player in the world, has been linked to McIlroy for nearly two years. She's now No. 10 in world standings.

Wozniacki put on a caddie's bib Wednesday for the Par 3 contest, and McIlroy even had her hit a shot, which she topped in the water. On Thursday, she was in the crowd following the Irish player during the first round.

McIlroy and Wozniacki were prominently featured on television coverage of the Par 3 contest, an informal outing for players and their families.

As far as lingering camera shots on celebrities during the tournament, ESPN spokesman Josh Krulewitz said:

"The focus of our coverage remains on the competition."

Celebrity couples aren't new to golf. Sergio Garcia once dated tennis player Martina Hingis, while Dustin Johnson currently dates Paulina Gretzky, daughter of hockey great Wayne Gretzky and actress Janet Jones.

— The Associated Press

All year long the worry about McIlroy was the way he was hitting the ball with his new Nike clubs. But in the opening round of the Masters, it was the putter that let him down.

"I felt like I played well," McIlroy said. "Just silly mistakes and a couple of 3-putts on the back nine."

A day that started with promise for McIlroy — he was 2-under after making birdie on No. 6 — turned bad on the final nine as he made four bogeys coming in. McIlroy played like he was rusty, the very thing he played two weeks in a row coming into the Masters to avoid.

He was six shots back of co-leaders Sergio Garcia and Marc Leishman, a margin that's certainly not insurmountable with three rounds left on Augusta National. But McIlroy will have to find a way to make the short putts he missed if he wants to be in contention going into Sunday.

The Northern Irishman came to the first major of 2013, hoping to jumpstart a year that so far has been a disappointment. He played well to get in contention at the Texas Open last week, finishing second with a final round 66, and expected to be in contention here.

But bad strokes on greens putting slower than usual made for one frustrating days.

"I'm hitting the ball well," he said. "It's just a matter of taking advantage of the opportunities and eliminating mistakes.

McIlroy looked to have gotten the worst of the draw with a pairing in the penultimate group as thunderstorms threatened. But the wind didn't gust as much as expected and the rain held off until just after McIlroy came out of the clubhouse after signing his card.

McIlroy started the day like he couldn't wait to get in contention. He barely missed holing a 50-yard pitch for eagle on the second hole and came close to making a second straight birdie on No. 3.

But after holing a putt for birdie on No. 6 he gave it right back with a poor second shot on the next hole, the first of a series of miscues that he was never able to recover from.

McIlroy conceded earlier in the week that the adjustment to his new clubs — which came as part of a huge endorsement deal with Nike — had taken some time. But he said his driving had improved greatly and he was gaining confidence with every round he played.

But McIlroy's problem in the first round came from his flat stick, not his driver. He hit 9 of 14 fairways but had 32 putts, including the two 3-putts.

If there was a positive for McIlroy it is that he seems to be beginning to feel very much at home on Augusta National, where he famously imploded in 2011 after taking a four-shot lead into the final round. A year ago, he was one off the lead going into the weekend, only to close with 77-76 and tie for 40th.

"Everything felt good but every time I did something good I gave it back," McIlroy said. "And around this course you can't do that."