Steve Stricker continued his historic run at the U.S. Senior Open Championship on Saturday in Notre Dame, Ind., shooting 4-under-par 66 to set the event's 54-hole scoring record and lead by six strokes entering Sunday's final round.

Stricker -- who held the best-ever 36-hole score by three strokes after Friday's round of 64 -- is at 18-under 192 for the tournament, besting previous marks of 15 under and 195, respectively, set by Kirk Triplett in 2017. His six-stroke lead is the second-largest through 54 holes in the event's history, one shy of Dave Stockton's edge entering the final round in 1996.

Sitting alone in second is Jerry Kelly, who shot even-par 70 to stay at 12 under. David Toms (70) is alone in third another stroke back.

Bob Estes (68) holds fourth place at 10 under, with a cluster of five players tied for fifth at 7 under.

Stricker, 52, put together his second straight bogey-free round, making birdies at Nos. 3, 5 and 7 to quickly expand his lead on the front nine. He added one more birdie at the 11th before parring the final seven holes.

"Just didn't get into too many problems," Stricker told reporters after his round. "That was the key. And if I did, I was able to get it up-and-down or make a save of some sort."

He's made just one bogey in the tournament, on No. 6 in the opening round, and has gone 17 under in the 48 holes since.

Stricker is playing in the event for the first time, seeking his second Champions major after claiming the Regions Tradition in May. He tied for second last week in a tournament he hosts, the American Family Insurance Championship in Madison, Wis.

"I think I'm just going to keep doing the same things I've been doing," Stricker said of his plan for Sunday. "My whole objective is to get it in the fairway and then see what pins I feel comfortable shooting at or steering away from. That's been the game plan, and I've been putting well."

Kelly struggled to gain momentum early, moving to 1 over with a bogey at No. 8 before making his first birdie at No. 11. He added a bogey at the 14th before a birdie at the 17th.

Toms, the defending champion, birdied the third hole but couldn't do more from there, posting 14 pars and one bogey (at No. 10) the rest of his round.

South Africa's Retief Goosen (72) is among the group tied for fifth. Germany's Bernhard Langer (70) -- a 10-time Champions major winner and the 2010 champion -- and Spain's Miguel Angel Jimenez (67), a runner-up in 2016 and 2018, are tied for 10th at 6 under.

After beating his age on Friday with a 68, 69-year-old Tom Watson fell out of the pack with a round of 73, leaving him at even par and tied for 38th.