Widnes coach Denis Betts thinks his team were out-battled by Salford after the Red Devils recorded a 30-10 win on Sunday.
The Vikings went into the game on the back of a 16-14 victory over St Helens last weekend, but they failed to follow up against an impressive Salford side.
Betts said: “Salford had a bit more energy and desire than us in the first half. We were completing well but we were not doing anything with the ball because there is no speed at our play the ball.
“We are not getting our half-backs into good positions. Salford ran harder and tackled harder than we did in the first half.
“It was disappointing because the attitude from some of our players was a little bit off especially at the start. We wasted a lot of energy.
“There are a lot of tired teams around this week after Easter and we looked really tired. We were okay but that’s not good enough in this competition. We started pretty well, but lacked some rugby smartness and a cutting edge.”