Watford head coach Walter Mazzarri praised the impact of the substitutes during their famous 3-1 home win over Manchester United.

Juan Camilo Zuniga came off the bench and fired the Hornets into a 2-1 lead with his first touch while Isaac Success also played a role in the move which won a late penalty and sealed the victory.

Mazzarri said: “I’m very happy because this [substitutes] is something we also have to keep working on, especially because also against Chelsea when you’re winning and you drop the mentality a little bit, you need to make some changes.

"The changes that we did today brought us a lot of confidence on the pitch and brought us the final result."

Zuniga, who was brought down for the hosts' penalty, has yet to start for the club. Mazzarri believes his match fitness is the only thing holding him back but felt he was the right player to bring on at a crucial point in the game.

The Italian said: “The only problem Zuniga has at the moment is for himself to have 100 per cent condition.

"But I wanted someone that is an expert player with a lot of experience. He’s very good technically and he came in and I’m very happy for him."