It’s hard to find a golfer who has been playing better than Jason Day since last August. Day won his first major at last year’s PGA Championship, and he hasn’t slowed down since, winning yet again Sunday at the Arnold Palmer Invitational.

Day continued his success for most of his matchup Wednesday with Graeme McDowell at the WGC Match Play Championships, but everything changed when he tweaked his back on the 15th hole at Austin Country Club.

And it got even worse on the 16th tee.

Day’s dominant play for most of the round allowed him to close out the match on the 16th hole with a 3 and 2 win over McDowell.

But he still was visibly hurt afterward.

“It’s really hard to play when there is searing pain in both sides of your back,” Day told The Australian Associated Press, via ESPN.com. “I’m really struggling. I need to get treatment right away to see what’s wrong.”

Day’s status for the rest of the WGC Match Play Championships is unknown but, as ESPN.com points out, the round-robin format means he could rest Thursday and still play Friday against Paul Casey.

Thumbnail photo via Soobum Im/USA TODAY Sports Images

Thumbnail photo via PGA Tour golfer Jason Day