Valencia came into Saturday’s clash having crushed Barca in exactly one of their past ten meetings in all competitions, winning last season’s Copa del Rey final, whereas their most up-to-date league success at the Mestalla came in February 2007.
But the Blaugrana were on the back foot from the beginning this time around and, whereas Marc-Andre ter Stegen saved a first-half spot-kick, Gomez made amends as his strike shortly after the restart went in off Jordi Alba for an goal.
Setien’s side belatedly rallied, however when scraping past Granada and Ibiza within the coach’s 1st 2 games in charge, their luck ran out, Gomez obtaining a goal himself with thirteen minutes remaining.
Real Madrid, not in action against Real Valladolid till Sunday, currently have the chance to pull 3 points beyond their bitter rivals at the top of the table.
Gerard Pique gifted Valencia a huge chance to take the lead after twelve minutes, his poor clearance prompting an attack that ended with the Barcelona defender clumsily chopping down Jose Gaya within the area.
However, Ter Stegen came to his team-mate’s rescue, brilliantly springing to his left to avoid wasting Gomez’s penalty.
Ter Stegen remained by far the busier of the 2 goalkeepers and awkwardly helped Gomez’s fierce drive onto the crossbar before parrying Kevin Gameiro’s follow-up wide.
Barca failed to actually threaten till the opening seconds of the last half once Ansu Fati ran onto Lionel Messi’s pass on the edge of the area however shot just wide.
It was Valencia who soon led as the indelicate away side struggled to clear, allowing Gomez to shoot hard and low from the right-hand side of the area, his effort deflecting off Alba to wrong-foot Ter Stegen and loop into the roof of the net.
Messi drilled past the right-hand post and sent a lob narrowly over the highest, before Jaume Domenech was equal to a 20-yard free-kick as Barca’s spell of dominance came too late to rescue a result.
Instead, Gomez got his goal, providing a clinical end on the far side the rooted Ter Stegen at the top of a Valencia counter-attack.