Jason Day overcame an early deficit to win his opening match in the Dell Match Play. Now he has to overcome a bad back.

Day was reaching for his back for a few holes until he grabbed it after a tee shot on the 16th hole and then dropped to one knee as he closed out Graeme McDowell, 3 and 2.

Day headed straight for the trailer to get it worked on.

At least he has one victory. Rickie Fowler rallied from 3 down on the back nine at Austin Country Club to square his match, only for Jason Dufner to win the next two holes in a 2-and-1 victory.

The round-robin format means Fowler can still win his group, though he will need help.