Jason Day survived a rollercoaster final round to complete a wire-to-wire victory in the Arnold Palmer Invitational and move above Rory McIlroy to second in the world rankings.

Day carded five birdies and three bogeys in a closing 70 at Bay Hill to finish 17 under par, a shot ahead of American Kevin Chappell.

Sweden’s Henrik Stenson, who has now finished third, second, fifth and eighth in his last four appearances in the event, was two shots further back alongside Troy Merritt, who surged into a share of the lead with five birdies in a row from the 10th, only to double-bogey the 18th.

Day took a two-shot lead into the final round and edged further ahead by chipping in for birdie on the second after a poor tee shot came up well short of the green, only to bogey the next two holes and fall into a tie with Chappell, who had birdied the third.

A birdie on the fifth took Day back in front but Chappell, who was playing in the penultimate group, two-putted the par-five sixth for birdie and then saw Day bogey the same hole after pulling his approach into the water.

Chappell, who is yet to win on the PGA Tour, briefly moved two clear with a birdie on the eighth, but promptly bogeyed the ninth before Day’s superb approach to the same hole left him a tap-in birdie.

Stenson made it a three-way tie for the lead with a birdie on the 10th but would go on to bogey the 14th and 16th, while Chappell moved back into the lead thanks to birdies on the 13th and 16th.

However, Chappell dropped a shot on the 18th to open the door for the chasing pack and Day birdied the 17th from 12 feet before saving par from a greenside bunker on the last to claim his eighth PGA Tour title and a sixth in just over 13 months.