Muguruza and Suárez Navarro were the biggest surprises of the tournament - they had beaten a slew of seeds to make it into the final, namely No.4 seeds Kveta Peschke and Katarina Srebotnik, No.6 seeds Raquel Kops-Jones and Abigail Spears and No.1 seeds Hsieh Su-Wei and Peng Shuai.
But while they were able to fend off three of the most powerful teams in the game, Muguruza and Suárez Navarro couldn't handle the mix of consistency and spins of No.2 seeds Errani and Vinci.
The Spaniards had good starts in both sets - 4-2 in the first set, 3-0 in the second - but the Italians bounced back each time, winning four games in a row to take the first set then six games in a row to take the second set. After an hour and 16 minutes they had the victory in straight sets, 6-4, 6-3.
"Tonight was a very tough match," Vinci said.
"Garbiñe and Carla are tough opponents and they had a great week. This is the second time we have won the title here in Madrid and are glad we could finish the week with another trophy."
It was Errani and Vinci's third WTA doubles title of the year, after the Australian Open (their fourth Grand Slam doubles title together) and another Premier-level triumph in Stuttgart two weeks ago.
Beyond that, Errani and Vinci extend their lead at No.1 the Road To Singapore doubles leaderboard - they were already almost 1200 points ahead of the No.2 team, and with this Premier Mandatory-level victory the Italians will have an even bigger lead when the leaderboard is updated on Monday.
Errani and Vinci now have 19 WTA doubles titles overall: two in 2010 (Marbella and Barcelona), three in 2011 (Hobart, Pattaya City and Palermo), eight in 2012 (Monterrey, Acapulco, Barcelona, Madrid, Rome, Roland Garros, 's-Hertogenbosch and the US Open), three in 2013 (the Australian Open, Paris [Indoors] and Doha) and now three in 2014 (the Australian Open, Stuttgart and Madrid).
Can they win their milestone 20th WTA doubles title together on home soil in Rome next week?