The 23-year-old from Holywood, Co Down, narrowly avoided missing disqualification on Sunday after mixing up his tee time for his singles match against Team USA's Keegan Bradley.
McIlroy was given a police escort to the course, after 27-year-old Erica Stoll, a PGA transport official at Medinah, raised the alarm that the professional was not on site.
With the help of Ms Stoll, her colleague Maggie Budzar (28) at the team hotel and Lombard Deputy Police Chief Pat Rollins, the golfer made it to his match, but with only minutes to spare.
McIlroy was due off in the third match of the morning, which was 30 minutes away when staff discovered he had not arrived at the club.
"I knew JP (JP Fitzgerald, McIlroy's caddie) had left about an hour earlier. I knew his (McIlroy's) tee time was 11.25 and he was the third group to go off. And we still hadn't seen him," Ms Budzar said yesterday.
Following a search of the players' 14th floor at the team hotel, housekeeping staff noticed that one room was still occupied.
McIlroy was emerging from his room on the phone to his manager Conor Ridge, when staff intercepted him at 11.52am.
"I woke up at 9am to call Caroline (Wozniacki, his girlfriend) who's in Beijing. I was up for a while. I was just hanging around," McIlroy said.
"I had a couple of missed calls from a number I didn't recognise so I didn't pick up. And then I got a phone call from my manager saying 'are you at the golf course yet?' I said, 'No, I'm not.'"