Jimmy Walker shook off a slow start Sunday to grab the 54-hole lead at the rain-soaked US PGA Championship.

Still searching for his first major win, Walker bogeyed three of his first eight holes in Round three - delayed until Sunday morning because of storms. Walker bounced back with four birdies and no bogeys on the back nine to shoot a two-under 68 and take a one shot lead at 11 under.

Jason Day shot a bogey-free 67 in to get within one shot of the lead at 10 under. Day had not birdied a par-five all week, but he ended that disappointing streak with a birdie on the 18th to end his third round on a high.

Day is trying to become the second player to successfully defend his title since the US PGA Championship moved to stroke play in 1958. The other is Tiger Woods.

"We just didn't really know what was going on with the weather, but I'm glad we got the third round in," Day told TNT. "I played some good golf today, so I'm looking forward to the final round."

Despite missing the last month with ligament damage in his ankle, Brooks Koepka shot a bogey-free four-under 66 — his third straight round in the 60s — to get to nine under. Koepka said before the tournament that he would not have played this week had it not been a major.

Henrik Stenson joined Koepka at nine under after he hit a brilliant 3-wood on the green in two at 18. Stenson shot a third straight three-under 67 in round three. The Open winner missed a number of close-range birdie putts, but still finds himself in great shape to win back-to-back majors.

The final round, under way as the third round came to a close, will be played with preferred lies, or "lift, clean and place". 

With persistent rain having affected the course, players experienced a lot of mud balls in round three, so the PGA made the decision to allow players to clean their ball in the fairway in the final round. Players will not be repaired so Walker and Robert Streb - seven under after the third round - will be the final pair.