Four behind the leaders, Americans Billy Horschel and Talor Gooch, McIlroy is still in with a chance of his first title of the year, but on this erratic, error-strewn performance he requires the full Magic Kingdom experience.

Starting two behind, McIlroy went out in a two-over 38 and when he bogeyed the 11th, his challenge was threatening to turn into a whimper. But there came a couple of upturns, with birdies on the 12th and 13th. At that stage he was only two off the pace and a fine, but blustery Florida Saturday was suddenly looking more palatable.

Inexplicably, McIlroy sliced it out of bounds on the 15th tee on the way to a resulting double-bogey and despite a birdie on the 16th, he was in freefall.

Bogeys on the 17th and 18th, left the 32-year-old in a tie for sixth alongside countryman Graeme McDowell on three-under. McDowell, in particular, will take hope from the fact that Bay Hill is a course that is becoming increasingly more difficult as it firms up still further. 

“I did really well to come back from the bogey on 11 with birdies on 12 and 13, and then just the tee shot on 15 killed me,” McIlroy said.

“I don’t want to say anything that I’m going to regret, but I guess, the last few years, we sort of know what to expect coming here. It just seems to be this way over the weekend. It’s just hard. It’s hard not to get frustrated.”

Vikto Hovland has to be the favourite, if only because he has won three of the last seven events, Yet, in truth, the Norwegian’s own 75 to fall back to six-under, one off the pace, hardly inspired confidence, regardless of the severity of the challenge. The two in the top four who did manage to shoot under par were Horschel (71) and Scottie Scheffler (68) on five-under. 

On the DP World Tour – formerly the European Tour – Scotland’s Ewen Ferguson takes a four-shot lead into the final round of the Magical Kenya Open as he seeks a maiden victory. Ferguson made an eagle and four birdies in a third-round 66 at Muthaiga Golf Club to reach 14-under, with Sweden’s Marcus Kinhult and China’s Ashun Wu on 10-under. 

Three birdies on the back nine gave the 25-year-old Glaswegian a welcome cushion, just three weeks after he finished 130th in a 132-man field in the Ras Al Khaimah Classic with rounds of 76 and 78.

Watch: World No 1 Jon Rahm misses 10-inch putt as Viktor Hovland takes two-shot lead at Bay Hill

As the Arnold Palmer Invitational reeled from the shock of witnessing world No 1 Jon Rahm not only missing a 10-inch putt but actually leaving it short, Viktor Hovland provided a reassuringly familiar sight on the upper rung of the leaderboard.

Hovland, the 24-year-old from Oslo, has won three of his last seven events and finished fourth in two of the others, a staggering run of form that has hauled him to world No 3. And with a win at Bay Hill, Hovland could leapfrog Open Champion Collin Morikawa to become No 2.

A second-round 66 gave Hovland the halfway lead. Seven birdies and one bogey took him to nine-under and two ahead of Northern Ireland’s Rory McIlroy, England’s Tyrrell Hatton and the American Talor Gooch. 

McIlroy’s putter was decidedly hot in his opening 65, but cooled considerably in this 72. It was a stark contrast to Hovland who only needed 23 putts.

“I knew I putted well, but I didn’t know it was that few,” Hovland said. “I just really saw the lines really well and was able to start it online. Sometimes when you see a couple go in early, it’s easy to keep that feel going throughout the day.”

Regardless of the current good nick of his game, Hovland is not the type to be complacent. There is also last year’s capitulation to keep him grounded in Orlando. Then he was seven-under and firmly in contention going into the weekend before he shot a 77 and a 78. “Yeah, that hurt me a little bit, but at the same time, I felt like I learned a lot,” Hovland said.

The old stamping ground of the late Arnold Palmer has always claimed its victims with its vagaries, although there was nothing at all sinister about the tiddler Rahm stepped up to on the par-three seventh. He hit it three inches and had no reason why.

“I wish I could give you all the excuses in the world, but no, it’s as simple as it just didn’t feel good in my hands, and I tried to stop, and I didn’t. It didn’t sit well in my hands. I was a little sweat and  I just simply didn’t stop,” Rahm said. “I don’t know. It was very odd. It sucks to give away a shot like that, to be honest.”