Rory McIlroy and J.T Poston each shot a bogey-free, 8-under-par 62 to tie for a one-shot lead over a packed field in the opening round at the Travelers Championship in Cromwell, Conn., on Thursday.

Fourteen players shot a 66 or better at TPC River Highlands, a welcome break from the scores at The Country Club in Brookline, Mass., the rugged course where the U.S. Open was contested last week.

It's like the anti-U.S. Open here," said McIlroy, who finished tied for fifth place in Brookline. "It's like U.S. Open rehab coming here. You're like, 'Oh, I can actually make some birdies. This is nice.'"

Poston made his birdies, too -- six of him in his first nine holes. Starting on the back nine, he carded a 29 as he made the turn.

"It was nice to kind of finally put some good swings together, hit some good shots and make some putts," he said.

In his past 10 tournaments, Poston missed the cut six times but finished tied for third at the RBC Heritage in April and tied for ninth at the Wells Fargo Championship in May.

"I feel like my scores and my results may not have shown that the last few weeks or months, but I felt like I was getting close, and I've been working hard at it," Poston said. "I guess today was kind of one of those days where it finally clicked a little bit."

The two hold a one-stroke lead over Xander Schauffele and Martin Laird, who recorded 63s, and are two up on Charles Howell III, Webb Simpson and Patrick Cantlay. Cam Davis and Matthew NeSmith shot rounds of 65 to sit three strokes off the lead.

Five more players are four strokes behind the leaders with a round of 66.

McIlroy, of Northern Ireland, played with a cold he caught from his young daughter.

"Energy levels are OK," he said. "I'm feeling a little under the weather, but it's just concentration at this point. I've got three more rounds left until I have a couple of weeks off and prepare for the Open Championship. I'm going to put everything into those three rounds."

Cantlay didn't have to cope with a cold -- just changing weather conditions that the afternoon group faced as the wind kicked up.

"I thought the conditions in the afternoon were a lot tougher," he said. "It was blowing as soon as I got on the first tee. Watching a little bit of the coverage this morning, I knew it was much different this afternoon than the low scores those guys put up this morning."

The course was unforgiving to Jordan Spieth, who shot a 5-over 75, mixing four birdies with five bogeys and two double bogeys.

--Field Level Media