Jason Day plays through the pain to edge frustrated Graeme McDowell

Jason Day ended up on his knees in pain but fought on to beat Graeme McDowell 3 and 2 on the opening day of the WGC-Dell Match Play at Austin Country Club in Texas.

The world No 2 — he can overtake Jordan Spieth and regain the No 1 spot if he wins the title for the second time on Sunday — came back from two down after four holes to put McDowell to the sword for the second time in this event.

However, it remains to be seen if the Australian will even play his day two match with Thongchai Jaidee today, with the Thai also unbeaten following his 2 and 1 win over Paul Casey in their Group 2 clash.