HILTON HEAD ISLAND, S.C. -- Turns out only the rain can stop Masters champion Scottie Scheffler.

Scheffler holed a difficult pitch for eagle on his second hole Sunday to build some separation in the RBC Heritage and looked so flawless that it was only a matter of time.

And then he ran out of time. A storm system with heavy rain stopped play for 2 1/2 hours, and Scheffler was able to get through only 15 holes when darkness forced a Monday finish. He led by five shots with no one seriously challenging him.

"Everyone is trying to chase Scottie, and he's making it really tough because he keeps winning," U.S. Open champion Wyndham Clark said after giving it his best effort.

Clark, who started the final round seven shots behind, opened birdie-eagle-birdie and at one point got to within one shot of Scheffler. He was 8 under through 11 holes until an adventure into the trees right of the 12th fairway led to double bogey.

Clark already has finished runner-up to Scheffler twice in this amazing run, at Bay Hill and The Players Championship in consecutive weeks in March. He at least managed to finish his round at 6-under 65 and posted at 15-under 269.

Patrick Cantlay and J.T. Poston joined him at 15 under and were just off the 18th green. Sahith Theegala also was 15 under and in the right rough on the 16th hole.

The final round is set to resume at 8 a.m. ET Monday. Scheffler has three holes separating him from a fourth victory in his past five tournaments, a level of dominance not seen on the PGA Tour since the prime of Tiger Woods.

The exception in his streak was a runner-up finish in the Houston Open when he misread a birdie putt from 5 feet that would have forced a playoff.

Now he is on the verge of becoming the first player since Bernhard Langer in 1985 to win the week after slipping on the Masters green jacket.

Scheffler was relentless as ever Sunday, especially at the end.

On the par-5 15th, he hit his second shot into the water fronting the green, which he assumes was due to mud on the bottom of his ball. Facing a fourth shot with trees blocking a direct path to the flag, he hit a shot with enough spin to ride the slope down to 12 feet.

The horn to stop play had already sounded. Scheffler chose to finish and lightly pumped his fist when he made it for par. That extended his streak to 66 straight holes at par or better.

Scheffler showed more emotion for that par than for his eagle on the second hole or the two birdies that followed.

"I felt like the par was pretty important tonight, just being able to go to sleep and still keeping a clean card," he said. "I felt like I got a bad break there in the fairway. I haven't had to hit a shot like that in a long time, so I figured there must have been mud on the bottom of the ball. Just nice to keep the card clean."

If it's a battle for second place -- just like it was at the Masters last week when Scheffler won by four shots -- there was reason for Cantlay and Poston to wait.

Second place alone is worth $2.16 million, some $800,000 more than a four-way tie for second.

Cantlay marked his ball next to the collar of rough left of the green. Poston was short of the green, some 30 yards from the back left pin.

No one has a chance of catching Scheffler unless the world's No. 1 golfer makes a series of blunders in the morning, and that looked improbable.

Scheffler has not made worse than par since a double bogey on the third hole Thursday. He had a streak of 53 holes -- dating to the 15th hole of the opening round -- without anything higher than a 4 on his scorecard.

He began the final round with a one-shot lead over Sepp Straka and asserted himself on the par-5 second hole. His second shot caught the back slope of a front bunker and shot it over the green, leaving him a pitch up toward mounds, short-sided given the green ran away from him.

It came off perfectly, bouncing short and right, crawling up the slope and feeding down into the cup. Scheffler just looked at his caddie, Ted Scott, his bottom lip slightly jutted as if to say, "Not bad."

And then every hole except No. 8, he was putting for birdie. He missed two chances inside 10 feet but handled the par-5 fifth with ease and holed a 6-foot birdie putt on the 13th when his approach narrowly cleared the steep railroad ties framing the front bunker.

All he has to do now is finish to collect another $3.6 million check before he heads home, where his wife is due with the couple's first child the following week.

Nine players have to finish, a group that does not include Tom Hoge.

Hoge elected to finish the 18th after the horn sounded. His tee shot sailed out of bounds. His fourth shot went into the native area, and Hoge chopped his way to a quintuple-bogey 9. That gave him a 74, dropping him from a tie for sixth to a tie for 18th.