Phil Mickelson immediately found himself $200,000 down at the start of his lucrative head-to-head match with Tiger Woods, after failing to birdie the first hole at Shadow Creek.
An eye-catching reward of $9million was on offer for the winner of Friday's much-hyped showdown in Las Vegas, broadcast as a pay-per-view event in the United States.
Yet Woods and Mickelson were also set to engage in a number of side bets, with the winnings from those going to charities chosen by the respective players.
The first side bet was agreed ahead of the contest when Mickelson said: "I feel like the first hole is a great hole for me. I'm willing to risk $100,000 that says I birdie the first hole."
Woods promptly urged his rival to double the bet, which Mickelson agreed to.
The five-time major champion looked well placed to back up his confident talk when he stuck his approach to nine feet after finding the opening fairway.
Mickelson's birdie putt slipped by, however, meaning he joined his opponent in settling for a par, with a smiling Woods saying: "That hurts the pocket."
"That hurts the pocket." - @TigerWoods
— PGA TOUR (@PGATOUR) November 23, 2018
Phil Mickelson pars the first and loses $200,000 on the first wager. Match is AS thru 1. pic.twitter.com/u1Z1HS42IM
Both players were introduced on the first tee by Hollywood superstar Samuel L Jackson.