Brooks Koepka is ready to pay Justin Thomas after the Tour Championship as he reflected on the "stupid bet" he made with his American countryman.

Thomas will take a two-stroke lead into the season-ending PGA Tour event starting at East Lake on Thursday, with Koepka three shots adrift.

But it seems Thomas is just about assured of at least one victory over Koepka after the two put a bet on for most hole-outs, the 2017 US PGA Championship winner stretching his lead during the BMW Championship.

Koepka said it was a silly bet to place and he is prepared to pay Thomas on Sunday.

"We were in Korea, we were playing together and we were talking about how all through the year we were going to have little action on how many times we hole-out," he told a news conference on Wednesday.

"I can't even remember the last time I holed out. I've got zero … I don't hole-out very much so it was a stupid bet on my part."

Koepka added: "I'll pay him on Sunday."

While he may lose that, Koepka still has a chance in the FedEx Cup despite the new format for the Tour Championship leaving him starting with a three-shot deficit.

The four-time major champion is not changing his approach as he eyes a first FedEx Cup title.

"It's another golf tournament – go out and try to win it. That's what you do every time you tee it up," Koepka said.

"Take one week at a time, go with the process and see where it puts you. Obviously I've got a good chance here, being third in the FedEx Cup, having a chance to win it.

"It's important, but I'm just going to go out and play some good golf this week."