ORLANDO, Fla. — Sam Saunders stepped onto the first tee at Bay Hill and flashed a quick thumbs-up to the crowd, the trademark gesture of his grandfather. For the next four hours, memories of Arnold Palmer were all around him Thursday.

Nothing hit him harder, though, than his walk to the 16th tee.

Parked next to the tee was Palmer's cart — that's where his grandfather loved to watch the action at the Arnold Palmer Invitational — and Saunders grew emotional.

"I started thinking about all the years that I've played in the tournament, and I just started thinking about him driving around in the cart and watching me," Saunders said. "And just to see it sitting there empty ... yeah, that's hard. I think we all feel that. I had my emotional moment, looked at it, and then got my head where it needed to be to play the next hole."

The first Arnold Palmer Invitational without the beloved tournament host began with Emiliano Grillo of Argentina and Matt Fitzpatrick of England opening at 5-under 67 to share the lead on a Bay Hill course that looked better than ever.

Saunders hit 5-iron from a fairway bunker on the par-5 16th and came up short into the water, leading to bogey. His 4-iron landed an inch from the hole and nicked the pin on the par-3 17th. And he went after the flag with a 6-iron on the 18th and again found water for a double bogey, leaving him at 74.

Even so, it was a big day.

The week is a celebration of Palmer, who died Sept. 25, for the tournament he brought to Bay Hill in 1979 and played until 2004, when he hit driver off the deck on the 18th hole with 16-year-old Saunders on the bag.

Saunders not only received a sponsor exemption, he was placed in the star pairing for the afternoon with Rory McIlroy and Brandt Snedeker. McIlroy twice made bogeys from the bunker and three-putted from 18 feet on the fringe in his round of 74.

Palmer's 29-year-old grandson was at Bay Hill to play, though he realized this was not a normal round. Asked how much he thought of Palmer, he said, "All day."

Grillo made two soft bogeys — a three-putt from 25 feet on No. 3 and missing the green from 120 yards in the fairway on the par-5 fourth — then came to life with seven birdies. That included a 50-foot birdie putt on No. 9 and a 40-foot birdie putt on No. 17.

Fitzpatrick played in warmer and slightly easier conditions in the afternoon, running off four birdies in a six-hole stretch around the turn.

LPGA: At Phoenix, Stacy Lewis missed a chance to shoot the second 59 in LPGA Tour history, settling for an 8-under 64 and a share of the first-round lead Thursday in the Bank of Hope Founders Cup.

Playing in low-90s heat in near-perfect conditions at Wildfire, Lewis was 9 under through 11 holes, parred the next six and closed with a bogey after hitting into the deep left greenside bunker.

Playing partner Ariya Jutanugarn, In Gee Chun, Katie Burnett and Sandra Changkija joined Lewis atop the leaderboard at Desert Ridge. All five played in the afternoon.