(Photo credit: Jeff Lange / USA TODAY NETWORK via Imagn Images)

Steven Alker of New Zealand sits atop the leaderboard at the ISPS Handa Senior Open thanks to an opening round of 7-under-par 63 on Thursday at Sunningdale in Berkshire, England.

Alker was buoyed by a 5-under 30 on the back nine that featured an eagle at the par-5 14th hole. He leads Australian Mark Hensby by one stroke.

'I was just efficient today,' Alker said. 'Drove it in the fairway when I needed to and iron play was solid and just made some putts, especially on the back nine, just kind of kept things rolling.'

One of the best senior players since joining the PGA Tour Champions in 2021, Alker has collected nine wins (including the Cologuard Classic in March) and two Charles Schwab Cups on the 50-and-older tour, but he'd like to add to his majors count. So far, he has won only the Senior PGA Championship in 2022.

'It's hard at our age just to keep it up and maintain our bodies, but just across the board, I probably don't practice as much as I used to,' Alker said of his consistency. 'I don't grind as much but I might spend more time on the body. Just try and balance everything and keep it in shape.'

Hensby's only senior victory to date was at the 2023 Invited Celebrity Classic. Now he's in contention for his first major, thanks to a white-hot start -- five straight birdies at the first five holes.

'I was hitting it really close. Like I said the first three holes I wasn't outside three feet,' Hensby said.

Joe Durant and South Korea's K.J. Choi, the defending champion, are tied for third at 4-under 66. A host of players are knotted at 3-under 67, including Irishman Padraig Harrington, Spaniard Miguel Angel Jimenez and Ernie Els and Retief Goosen of South Africa.

Jimenez and Harrington won the past two majors -- Jimenez at the Kaulig Companies Championship, Harrington the next week at the U.S. Senior Open.

Harrington was befuddled by his round, in which he was even par through 12 holes, birdied Nos. 13-15 and No. 17, then bogeyed the last.

'I played lovely at the start and struggled to score well,' he explained. 'I had a really bad three-putt early on and took three from the edge of the green. Then on the back nine, I didn't play so well and scored great. I chipped in on 13. Holed a nice putt on the two par 3s.

'Yeah, disappointing to three-putt the last.'

--Field Level Media