Rory McIlroy continues to struggle at Players Championship

The world number 42, who was second in the Wells Fargo Championship last week, birdied the first, second, fourth and ninth to reach the turn in 32, before picking up further shots on the 12th, 13th and 17th despite the blustery conditions.

A bogey on the 18th was the only blemish on Perez's scorecard and lifted him to within five shots of the lead shared by former Open champion Louis Oosthuizen and American Kyle Stanley.

In contrast, McIlroy was still struggling to rediscover his top form in his first event since the Masters, after which he got married and signed a multi-million pound equipment deal with TaylorMade.

McIlroy, who will have an MRI scan on Monday after suffering a recurrence of the back problem which ruled him out for seven weeks earlier this season, made the ideal start with a birdie on the first.

But the four-time major winner then bogeyed the fifth and although he did birdie the ninth for the third day running, he was unable to pick up further shots on the par-five 11th or short 12th, where his long-iron tee-shot bounded through the green.

Bogeys at the 14th and last bookmarked back-to-back birdies at the 16th and island-green 17th and at one under par McIlroy was eight shots off the pace and five behind 54-year-old Fijian Vijay Singh, who was looking to surpass the 52-year-old Sam Snead as the oldest winner in PGA Tour history with his first victory since 2008.

The former world number one is suing the PGA Tour - which is based at Sawgrass - for ''reckless administration and implementation'' of its anti-doping program after he was banned for using deer antler spray in 2013.

The ban was subsequently rescinded when the World Anti-Doping Agency said it no longer considered use of the spray to be a doping violation without a positive test, but Singh filed a lawsuit in New York claiming the Tour's actions left him "humiliated, ashamed, ridiculed, scorned and emotionally distraught.''