However, he put in a poor round of one-over par in Atlanta as he finished joint-second with Jim Furyk on eight-under for the tournament.
"I'm looking forward to a few days off and not seeing my golf clubs for a little while," McIlroy told reporters.
"I've been in the gym every day this week and that's fine, but mentally I'm a little fatigued. Billy deserved it, he played the best golf all week."
McIlroy is part of Paul McGinley's European side for the Ryder Cup, which begins on September 26.