Rory McIlroy faced a massive task to defend his US PGA Championship title and his status as world number one at Whistling Straits on Sunday.
McIlroy began the final round of the year's final major championship nine shots behind Australia's Jason Day, but also crucially seven behind world number two Jordan Spieth.
Masters and US Open champion Spieth had four chances to overtake McIlroy in the world rankings, with a third major title of the year - matching the feats of Ben Hogan in 1953 and Tiger Woods in 2000 - meaning McIlroy would have to finish outright second to keep top spot.
Outright second would be enough for Spieth if McIlroy did not finish in the top six, or a share of second with one other player if McIlroy was outside of the top 13.
Spieth could also claim top spot by finishing tied second with two other players if McIlroy was not in the top 33, but anything lower than outright third for the 22-year-old American would ensure McIlroy stayed top of the pile.
As the final pair started with pars on the opening hole, McIlroy had birdied the sixth and seventh to improve to eight under par and a share of 12th place, the 26-year-old performing superbly on his return from an ankle ligament injury which meant he could not defend his Open and Bridgestone Invitational titles.
Ryder Cup team-mate Martin Kaymer was the first of the later starters to make a move up the leaderboard, the 2010 champion at Whistling Straits holing from six feet on the third to move to 12 under, three behind Day.
Source: PA
