Rory McIlroy believes he took a positive step forward with a four-under-par 68 in the first round of the Frys.com Open.

As the Northern Irishman departed to explore the vineyards of Napa Valley, California, he reflected on a solid 18 holes at the Silverado course, which is situated in the heart of the wine country.

Starting on the back nine in mild early-morning conditions, McIlroy dropped an early shot at the 13th, but as the mercury climbed so the scoring improved, and he made birdies at the 15th, 18th, first, fifth and eighth.

“It’s definitely better — better from tee to green than I was at the Tour Championship a couple of weeks ago, so it’s definitely a step in the right direction,” McIlroy said.

“I didn’t hole many putts — I holed a few — but if I can get the putter going over the next three days hopefully I can get up the leaderboard a bit.”

McIlroy finished 16th out of 28 finishers at the Tour Championship last month, 10 shots behind champion Jordan Spieth.

McIlroy’s score on Thursday, as he alluded, was not pace-setting form. It left him locked in a 16-player tie for 13th place, but heartened all the same.

The lead was held by American Brendan Steele, whose opening nine holes were exceptional.

After a par at the 10th, his opening hole, Steele then made birdie at seven of the next eight to surge to seven under par at the turn, picking up further shots at five and six to post a nine-under 63.

Venezuelan Jhonattan Vegas was one back, while Harold Varner III stood third on seven under and was joined on that mark late in the day by Scotland's Martin Laird, who made four birdies over the final six holes for a 65. Fifth was shared by Justin Thomas and DH Lee.

Justin Rose, who played in a group with McIlroy and Brandt Snedeker, was the leading Briton after a five-under 67 that put him in a share of seventh position.

The Englishman recently gained a new driver, and said on the pgatour.com website: “This is a golf course where you have to drive it well and if you do drive it well round here you set up a lot of birdie chances.

“The par-fives are all in range, then there’s lots of par-fours where you’ve got wedges into the green, that’s why you’re seeing some guys going low, but it’s also a tricky course, it has its subtleties. If you play well you can go low but it’s going to find you out if you’re not on your game.”

American Daniel Berger was four under through 10 holes but faded and signed for a two-under 70.

This tournament, the first of the new season on the PGA Tour, would not usually be able to call on the players ranked third and seventh in the world given its position in the calendar.

Yet McIlroy and Rose were among eight players who entered a non-sanctioned match play event called the Turkish Airlines World Golf Final in October 2012, which was staged at the same time as the Frys.com Open.

And in return for being granted a release to play in Turkey — where Rose won 1.5million US dollars for beating Lee Westwood in the final — all eight players had to agree to make the trip to Napa Valley at least once during the next three years.

Discussing the appeal of the tournament, McIlroy said there was more than golf to interest him in the region.

“It’s a nice event. It’s a beautiful part of the world,” he said. “There is a lot of stuff to do off the golf course as well. Just trying to find a balance between not feeling too hungover when you tee it up the next day.”