WASHINGTON (AFP) — US rookies Kevin Velo and Isaiah Salinda grabbed a one-stroke lead after Friday’s alternate-shot second round of the PGA Zurich Classic while defending champions Rory McIlroy and Shane Lowry charged into contention.

Velo and Salinda, each seeking his first PGA Tour title, combined to fire a three-under par 69 to stand on 17-under 127 after 36 holes in the pairs event at TPC of Louisiana in Avondale, Louisiana.

“Overall, really solid. We played really to our strengths today,” Velo said.

“We played pretty flawless. We feed off each other really easily.”

Americans Ben Griffin and Andrew Novak, also chasing their first PGA wins, combined for a 66 with birdies on three of their final five holes to stand second on 128, one stroke ahead of Danish twins Rasmus and Nicolai Hojgaard.

“We’re both in solid form right now, feeding off each other,” said Novak, who lost a playoff to Justin Thomas at last week’s Heritage event.

Back-nine starters Salinda and Velo, pals since their junior golf days, were one-over through nine holes but reeled off three birdies in a row to start their second nine and share the lead. Salinda’s birdie putt from just inside 12 feet at the eighth put them alone at the top.

“I like our chances in alternate shot versus anyone in the field,” Salinda said.

“We just keep playing how we’re playing, set ourselves up for Sunday and give ourselves a shot.”

McIlroy and Lowry were six-under after 12 holes but stumbled with bogeys on three of the last six holes to shoot 69 and finish on 11-under 133 entering Saturday’s four-ball format third round and Sunday’s alternate-shot final round.

“We were six-under through 12 and cruising and then a bit of a bad finish but I didn’t feel like we played that badly to have the finish that we did,” McIlroy said.

“A couple of loose shots here and there.”

“Tomorrow it will be hard to stay patient because in the four-ball format you just have to try to make as many birdies as you can.”

Northern Ireland’s McIlroy, in his first event since winning the Masters two weeks ago to complete a career Grand Slam, and Irishman Lowry want to become the event’s first back-to-back champions.

McIlroy, who has already won three titles this year, sank an 11-foot eagle putt at the par-5 second but Lowry missed the green and a par putt to bogey the par-3 third.

McIlroy made a birdie putt from just inside 15 feet at the fourth and Lowry pitched from the rough to just inside five feet to set up a McIlroy birdie putt at the par-5 seventh.

Lowry dropped his approach inches from the hole at the eighth to set up a McIlroy tap-in birdie and landed his approach at the 10th inside four feet to set up another McIlroy birdie putt.

At 12, McIlroy sank a 14-foot birdie putt to lift the duo to 14-under and a share of second.

But at 13, McIlroy couldn’t reach the green from the rough and missed a 20-foot par putt.

Lowry missed the green at the par-3 17th and they needed four shots to reach the green in taking a bogey at the par-5 18th.