Rory McIlroy's comeback from injury has been blighted by a stomach bug, but he showed has the guts to compete against the odds in round two of the WGC-Mexico Championship at Club de golf Chapultepec near Mexico City.
McIlroy woke at 3.0am on Thursday morning feeling ill, but made it to the first tee and opened with a three-under par 68.
He had not eaten much food through to his tee-off time for his second 18 holes yesterday, but nobody would have realized that as the Northern Irishman battled his way to the top of the leaderboard, shooting 65 to lead the tournament by two shots on nine-under par.
His nearest challengers were England's Ross Fisher, American hero Phil Mickelson and compatriot Justin Thomas who each managed to stay in touch with McIlroy on seven-under par.
The margin could have been greater from a McIlroy perspective, as the four-time major champion missed good birdie chances on the 16th and 18th as well as bogeying the par-three 17th where he took three putts from 21 feet.
"Going out starting the day I would have taken a 65. I'm in a great position going into the weekend, but I feel like I could have been few more ahead," said McIlroy.
McIlroy blistered his way through the front nine to turn in 31 courtesy of four birdies.
He had a blip on the par-4, 12th where he was bunkered off the tee, and finished with a bogey five.
On the 225 yards par-3 13th, one of the toughest holes in the course, he holed from 12 feet for a birdie two.
Then came his shot of the day on 14 when he holed a 9-iron shot from 152 yards for an eagle two to move to -6 for the day, and nine-under for the tournament.
McIlroy would be the first to admit he got some luck, but he deserved it.
He slightly tugged the ball to the left as it flew high to the green. It bounced off the edge of the rough, took the slope and rolled slowly into the cup.
When his game is hot, McIlroy burns his way through the field, and he pitched and putted for a birdie four at the par-5 15th to get to ten-under.
The last three holes were not as spectacular as the previous three but it was a job well done.
Mickelson too had a good day but his long-serving caddie, Jim 'Bones' McKay, was laid low by a stomach bug which forced him off the course after three holes.
He got sick overnight and Mickelson's brother, Tim, who is Jon Rahm's manager, immediately took over the caddie duties.
"Bones is one of the best in the business, but my brother's a good player in his own right," said Mickelson.
Meanwhile, Paul Dunne safely made the cut in the European Tour's Tshwane Open in Pretoria yesterday to enter today's third round on one-under-par overall after rounds of 73 and 68.
Bad weather caused delays before 81 players earned their passage into the weekend. The cut mark was level-par. Darren Clarke was not among the qualifiers. His run of missed cuts continues after finishing on nine-over 151 (74, 77).
The joint leaders were Scott Jamieson of Scotland and Sweden's Alexander Bjork.
They shot 65 and 67 respectively to lead the field by one on 10-under-par.