Tony Smith was left to rue the "Gareth Hock show" as Widnes shocked his Warrington side.
England international Hock, on loan from Wigan, was a dominant force in the 38-22 victory and Smith had no complaints about the result.
"I don't think we played well enough to win that game," Warrington boss Smith said. "We had a period after half-time where we could have taken control but we weren't able to do that.
"The enthusiasm of Widnes was terrific. Their support was great and defence was pretty solid.
"They have gone back to the drawing board and they deserve all the credit they will get from this victory.
"Widnes were better and deserved it. It was the Gareth Hock show. He was the best player on the field. He came up with some big plays and he was great for them. He was so instrumental."
The Vikings' victory came just a week after Widnes were embarrassed 62-4 at Wigan but coach Denis Betts was still not entirely happy.
"We still need to look at the second-half start but we were solid," Betts said. "Warrington are a tough side and difficult to break down but we did it.
"We are notching a few big scalps off. We are putting our mark down and building our confidence. I thought Warrington were really good and had a go at us but we stuck in.
"There's plenty of players who were impressive today. Rhys Hanbury was great but our best player on the field was Jon Clarke, he was outstanding - absolutely unbelievable.
"We are getting better and better. We have some options and no one is guaranteed a spot. We are generating competition and the players want to keep the jersey."