Barnsley head coach Valerien Ismael was proud of his team's performance to see off a strong Watford side 1-0 at Oakwell in the Sky Bet Championship.
Alex Mowatt scored the only goal in just the sixth minute, when his strike from outside the area flew in off the inside of the post.
The Tykes were the only team in the first half to create any chances on goal. Dominik Frieser fired well over from the edge of the area and Conor Chaplin had a weak effort that was easy for Watford keeper Ben Foster to collect.
Watford dominated the second half as they looked to get back into the game.
Their best chance came through their dangerman Ismaila Sarr. The forward got by his man, drove towards goal from a narrow angle and his cut-back found Tom Cleverley, who fired wide from just six yards.
Defender Ben Wilmot could have also grabbed an equaliser but his header bounced up off the turf and went just over the bar.
After leading his side to a second win in a row since taking over, Ismael said: "I'm very proud of the guys. It was a tough game against a very strong team today in Watford.
"The first half was perfect; we made the perfect start and did exactly what we wanted. We pressed high, won the ball in the opponent's half and got towards their goal quickly.
"We created a lot of good situations. Sometimes we had to adapt because of the way Watford played but we did well.
"The second half was a big fight, but we needed such a game to show we can adapt to the Championship and it's a good feeling today.
"We don't have the possibilities like Watford – when you see their roster, it is very wide. In every game we have to invest a lot of energy and today showed when we do that, we can beat anyone. This win will give us a lot of confidence and belief."
Watford head coach Vladimir Ivic admitted his side did not take their chances.
He said: "We only started to play after the goal we conceded. We had more mobility maybe than in some previous games, but it still wasn't enough.
"We created the opportunities to score but we couldn't get the shots on target and because of that we are disappointed. We made a mistake and the guy from Barnsley scored a fantastic goal. We know that if we make mistakes then they will punish you.
"It's a game that didn't give us what we want but we need to rest now and think about the next game because it's on Wednesday and it will be tough.
"In this tough rhythm of games, it is most important that we rest the players and to understand that we must give more because we can give more, and we must start to win games again."