Jason Day capitulation leaves door open for Dustin Johnson

Dustin Johnson won the WGC-Bridgestone Invitational after Jason Day's late collapse on Sunday.

The US Open champion hit a four-under-par final round of 66 to chase down world number one Day and win by one shot in Ohio — his first tournament since his maiden major win last month.

Three birdies and a bogey on the opening nine set him up and three more, including a birdie at the 17th allowed Johnson to take control.

Johnson moved up to number three in the world golf rankings after his win at Oakmont, and will now head to The Open in fine form following his third World Golf Championship victory.

A bogey at the last saw Johnson as the clubhouse leader and Day, the 2015 PGA champion, fell apart as he carded a bogey on the 15th and then a double bogey on the 16th.

He tumbled to joint third on three under par with Jordan Spieth, Matt Kuchar and Kevin Chappell as American Scott Piercy took second at five under.

Paul Casey finished tied for 16th and Justin Rose finished 10 over par in 46th.

Defending champion Shane Lowry closed with a 68, leaving him six over par for the tournament and tied for 36th place.