The British number four seed pummelled his way past the Colombian 6-3 6-4 6-4 under a burning Parisian sun.
Moving freely around the court, the Scot was almost unrecognisable from the figure who had pain etched into his features in his second round clash against Jarkko Nieminen.
At that point his hopes of capturing a maiden Grand Slam at the French Open appeared to have turned to red dust as he lay prone on Roland Garros clay and needed three massages to treat his aching body.
It was an altogether more optimistic player who faced the media after wearing down his opponent's fragile resilience to book a fourth round clash against France's Richard Gasquet.
"It was very hot today, so I warmed up very quickly," he said.
"I woke up this morning again feeling better than I did, but that's because of the work my physio has done the last 48 hours and all the recovery work that we've done between the last match and now.
"With the rest and doing all the right things, I felt better."
Murray broke in the sixth game of the first set and never looked like relinquishing control as his never-say-die defence and a series of rip-roaring forehands took their toll on Giraldo who had never gone beyond the first round here until this year.
If the acid test of a back injury is a player's ability to serve then Murray's perfect game of four straight aces in the second set is positive sign heading into the second week.
"I felt like I moved pretty well today," he said. "When you're playing in slams, I just think each day you need to take as it comes.
"I'm hoping that tomorrow I'll feel good again, and that's all you've got to do, each day just be a little bit better."
Next up for Murray is the 17th seeded Frenchman, who has played Murray three times in Grand Slams, twice at Wimbledon and once at Roland Garros, with the Briton winning them all, although Gasquet was leading by two sets in two of them.
"I wouldn't necessarily see myself as the favorite for the match," Murray said.
"Obviously he beat me a couple of weeks ago (at the Rome Masters). He's going to have the crowd behind him and I think right now this is probably his best surface.
"So it's going to be a tough match, but when I played him here last time, I hung in, I fought really hard, and just managed to turn the match around, and I did the same thing at Wimbledon.
"When he plays well, he's a very tough guy to beat. He plays some unbelievable shots."