Alaves continued their excellent home form by recovering to beat struggling Spanish powerhouse Valencia 2-1 on Saturday, climbing into fourth place in LaLiga and boosting their chances of qualifying for the Champions League for the first time.
Valencia captain Dani Parejo gave the visitors the lead with a swerving free kick in the 14th minute but Alaves, who are the only side in Spain's top flight alongside Atletico Madrid to still be unbeaten at home this season, soon hit back.
Striker Borja Baston pulled the 2001 UEFA Cup runners-up level in the 21st with a scrappy, deflected shot from inside the area, while midfielder Tomas Pina put Alaves ahead in first-half stoppage time after a period of heavy pressure.
The win took Alaves to 31 points from 18 games, one ahead of European champions Real Madrid who host Real Sociedad on Sunday, and saw the Basques reach their highest points total in the first half of a La Liga season.
"It's unbelievable that we have got to 31 points at this stage and our performance today was also unbelievable," said Alaves coach Abelardo Fernandez, who inherited a side struggling for La Liga survival when he took charge 13 months ago.
"We played so well in such difficult conditions, on an icy pitch and against a team like Valencia who gave everything. I'm so grateful to our players and our supporters."
Valencia, who finished fourth last year, are 11th on 22 points after a defeat that will pile more pressure on coach Marcelino, who last month faced calls from fans to be sacked.
"What happened today has a difficult and simple explanation," Marcelino said.
"We started well on a pitch that was impractical and that was half frozen. Then we conceded two goals from set plays, their biggest weapon, both of which were avoidable."
Meanwhile, LaLiga strugglers Rayo Vallecano grabbed a nervy 1-0 win at Real Valladolid on Saturday to boost their chances of top-flight survival, although they had to rely on a late penalty save to take all three points.
Midfielder Alvaro Medran gave the Madrid minnows a perfect start by scoring after 29 seconds, finishing off a smart team move from close range to score the fastest goal of the season so far in La Liga.
Valladolid, who are 14th and without a home league win since October, were awarded a penalty in the 87th minute but Rayo's Macedonian goalkeeper Stole Dimitrievski guessed the right way to palm midfielder Michel's spot-kick away.
Rayo, who are second-bottom still had to withstand a series of hurried late attacks from the hosts but held on to claim a second consecutive victory for the first time this season.
The win took them level on 16 points with the two teams above them, Athletic Bilbao and Villarreal, who are both in action later this weekend.