The World Number One entered the week looking to become just the second player after Seve Ballesteros to win this event three times in the European Tour era and just the fourth player in history to win the same regular European Tour event three times in a row.
He started round three just a shot off the lead but weekend scores of 72-69 saw him finish at 13 under, six shots out of the play-off won by another local favourite in Rafa Cabrera Bello.
Rahm has taken huge crowds with him wherever he has gone this week - fans he has called "golf hungry" after the Covid-19 pandemic - and they were still there watching their hero as he finished on Sunday.
And before he set off for Real Club Valderrama to delight another set of Spanish fans at next week's Estrella Damm N.A. Andalucía Masters, he stayed behind for countless autographs and selfies.
"I'm going to sign all the children, no matter how long it takes," he said.
A true credit to the game.