The victory from fifth seed Lopez helped to ease the pain for a country which has won two of the last three titles here (through Nicolas Almagro and Marcel Granollers) after the second-round eliminations earlier of a pair of compatriots.
Guillermo Garcia-Lopez was crushed 6-1, 6-2 as Argentine Juan Monaco won his opening career match at the elite alpine venue located at 800 metres above sea level in a quiet pedestrianised village.
Monaco, champion two months ago in the dirt in Dusseldorf, won his 18th match of the season on clay, taking 64 minutes with four breaks of serve.
There was more Spanish disappointment for Pablo Andujar, beaten in just over two hours 6-3, 4-6, 6-3 by Russian sixth seed Mikhail Youzhny, who welcomed nine double-faults from his rattled opponent and who broke on five of 16 chances.
Lopez wasted no time in advancing, winning the opening set with a break of serve against Kuznetsov and then taking a 5-3 lead on his second break of the sunny afternoon before booking into the last eight after little more than an hour on the fast clay.
Swiss second seed Stanislas Wawrinka was due to open after a bye awarded to the top four seeds, when he faced another Spaniard in Daniel Gimeno-Traver, whom he beat on clay in Argentina four months ago.
2004 champion and 17-time grand slam winner Roger Federer takes the top seeding but will not start until Thursday when he faces German Daniel Brands in the second round.
Federer will be willed to win by a capacity crowd, some of whom will be occupying the 800 additional seats installed in the expanded grandstands shortly after the tennis icon announced his return in the wake of a Wimbledon second-round disappointment last month.
History repeated itself in a welcome ceremony, with Federer being presented on court with his second milk cow by the event which did the same for him in 2003 after he won his first Wimbledon trophy and then travelled to the alpine village to play the ATP event.
“She won’t be in my trophy room, that’s for sure,” joked Federer, whose twin daughters turned four this week. “Now I need to find a garage for a cow, although I have no idea what a cow garage looks like.”