Tiger Woods faces a battle to beat the cut after he endured a difficult time in his first round on the PGA Tour for almost 18 months.

The former world No1, who has been plagued by back injuries, fell apart on the back nine to card a four-over-par 76 at the Farmers Insurance Open in San Diego. Playing the more demanding of the two courses being used at Torrey Pines, the South, Woods was one over par at the turn and things were looking up when he birdied 10 and 11.

But things quickly unravelled as he bogeyed the next three holes, followed it up with a double bogey at 15 and then went one over again on 17. He did at least finish with a birdie on 18, but it was the 41-year-old’s highest opening round to begin a PGA Tour season since he turned professional in late 1996.

He has it all to do on Friday if his return is going to be extended to the weekend.

Woods has undergone two back operations since his last regular tour appearance in August 2015. After a long lay-off he finally returned to tournament play at last month’s Hero World Challenge in the Bahamas but his rustiness was evident. He said: “I fought my tail off today.”

Olympic champion Justin Rose is the first-round leader on seven under. Rose, playing on the North, sank two eagles in the opening nine holes to make the turn at six under and he recovered from back-to-back bogeys on 14 and 15 with successive birdies to card a 65.

He heads to the South Course on Friday in good shape and knows he had to make his opening round count. He said on Sky Sports 4: “I have been practising well at home. It was nice to get off to a good start and show my range practice pull through. It can be a tricky week. The South Course is really tough and if you don’t go low on the North Course you are going to feel like you’re behind.

“I have been making some putts and I drove the ball really well, especially on the key holes, the par fives.”

He is one shot clear of Canada’s Adam Hadwin, while Gary Woodland Brad Fritsch, Charles Howell III, Beau Hossler and Trey Mullinax are all a shot further back on five under.

Meanwhile, Graeme McDowell vowed not to get carried away after starting his 2017 campaign with a superb opening round in the Qatar Masters. The former US Open champion looked close to his best as he took advantage of unusually calm conditions to card a six-under-par 66 and lie two shots off the pace set by Welshman Bradley Dredge. “My expectations were fairly low, I suppose, coming in,” said McDowell, who had failed to card a single birdie in the pre-tournament pro-am. “My game felt a little bit rusty the last week or so and I was expecting tougher conditions. Now that I’ve got off to a good start, I’ve got to keep my expectations in check and not get too far ahead of myself, just keep calm and keep enjoying myself and stay patient and see what happens.”