Andrei Ratiu scored on his return to the line-up having been dropped against Barcelona, while Sergio Camello netted a second-half double to move level with Raphinha atop LaLiga's scoring charts on five goals apiece. The victory came away from Vallecas, with Rayo Vallecano still playing home fixtures elsewhere while renovation continues on their own stadium.
"Very important, we needed it. It wasn't just about winning but how," Beñat San José said.
"We put on a spectacular, very complete performance. The players were perfect and executed the game plan exactly as we practised during the week.
"The sendings-off hurt us a lot â we ended up with three players dismissed in the blink of an eye. We want to dedicate this win to Augusto Batalla."
San José was full of praise for Camello's contribution to the turnaround.
"He's very complete, he works so hard for the team. He carries the DNA of our style of play," he said. "He's a No 9 who can score a goal or set one up, and he can also play as a false nine or a No 10 to create superiority between the lines. He has to keep working because he knows I'm going to demand even more from him."
The Basque coach was scathing about the officiating that led to his side finishing with eight men.
"The referees told me Jorge De Frutos was sent off for kicking a fridge. I haven't seen the report. I respect referees a lot and we can all make mistakes, but sending off a player for that is harsh," he said.
"As for Fran, that's their decision, but my opinion is that it was a natural football incident that didn't merit a red card. I don't know why they sent off my assistant â I didn't hear any insult from the bench."
Racing Santander boss José Alberto felt his side had done enough to take something from the match.
"After scoring two goals away from home, as difficult as that is, we can't lose. We have to improve defensively â I think we deserved to get something from this game," he said.
He was particularly aggrieved by a disallowed goal.
"My player doesn't touch Cårdenas at any point, this is football, not basketball. I think VAR has to intervene in such a clear-cut incident," José Alberto said. "I'm leaving very unhappy because I think we've been harmed. The referee didn't want to give me any explanation for the disallowed goal."
The Racing manager added his side had lacked control in midfield, with new arrivals still finding their feet.