South African Louis Oosthuizen was battling with a long-standing back problem as well as Jason Day when the last eight of the WGC-Accenture Match Play Championship began in Arizona.
Oosthuizen received lengthy treatment from his personal physio before play started and looked to be in real trouble as he carved his opening tee shot into the desert.
After attempting to hack clear from a bush, Oosthuizen quickly conceded the hole to Day and seemed likely to fall two down after another errant drive on the second.
However, this time the former Open Champion took a penalty drop and then hit a superb third shot with a fairway wood on to the green, holing the putt from 20 feet for an unlikely winning birdie.
Another birdie on the third briefly took Oosthuizen one up, but he made a mess of the fourth with two bad pitches and went behind to a Day birdie on the fifth.
Rickie Fowler made a flying start in the quarter-finals to leave opponent Jim Furyk facing a familiar uphill task.
Fowler, the beneficiary of Sergio Garcia's sporting concession on the seventh hole of their third round clash on Friday, needed no outside assistance when play in the last eight got under way at Dove Mountain.
Birdies on the first, second and fourth put the 25 year old three up on former US Open Champion Furyk, who had reached his first quarter-final in this event at the 14th attempt, despite trailing by at least two holes in all of his matches.
The remaining quarter-finals saw Ernie Els take on Jordan Spieth and a clash between the last remaining European players Graeme McDowell and Victor Dubuisson, although there was a gap of 90 minutes between the start of Fowler's match and that of Els.
McDowell had played 58 holes to reach the quarter-final and had remarkably never stood on any tee with the lead, producing miraculous comebacks to edge past Gary Woodland, Hideki Matsuyama and Hunter Mahan.
But the former US Open Champion needed just two holes to finally get his nose in front against Dubuisson, an eagle on the par five second taking him one up and leaving the Frenchman facing a deficit for the first time this week.
Furyk had got back to one down against Fowler before making a mess of the ninth to trail by two holes at the turn, while Day had birdied the ninth and been conceded to at the 11th to move three up on Oosthuizen.
Els had somehow made the last eight despite being an approximate four over par for his first three matches, but set about improving that statistic with birdies at the second and third to take a one hole lead over Spieth.
McDowell went further ahead with a birdie on the third, but was pegged back by a birdie from Dubuisson on the fourth before the fifth was halved in untidy bogeys.
Fowler was closing in on victory after a birdie on the 11th took him three up on Furyk, but Oosthuizen still had hope of a comeback after taking the 13th to get back to two down against Day.
