The West Brom manager was delighted with the positivity shown by his players as goals from Morgan Amalfitano and Saido Berahino saw off David Moyes's side at Old Trafford
The Baggies earned their first victory against the Red Devils in 29 years as Morgan Amalfitano and Saido Berahino struck in the second half to consign the hosts to their third league defeat of the season.
And Clarke feels that his players' positivity was behind the result, enthusing to reporters: "I think anybody that was listening to me before the game would know that I said I was coming here to be positive, we were coming here to try and play.
"Thankfully my players were listening because they did that - I thought we were tremendous from start to finish.
"We did everything almost perfectly and, when you come to Old Trafford and you're playing against the reigning champions, you need to play almost the perfect game and we did that.
"We created a lot, we looked dangerous, we passed the ball well. All I can do is praise the players; I thought defensively we were strong, we created in midfield, we passed the ball well and we looked a threat every time we went forward."
Clarke was forced to withdraw winger Scott Sinclair due to injury just 13 minutes into the game, with goalscorer Berahino introduced as his replacement, and the former Chelsea coach emphasised the importance of sending on another attacker to the win that followed.
"Saido deserves his place in the team, he's had a good impact for me," he added. "He's got a goal in him, as you can see, and I just felt, at that stage, we were playing well, we were in the game and I wanted to stay positive.
"I didn't want to send a negative message to the players by maybe bringing on a more defensive-minded player, I wanted to bring on another attacker and fortunately it worked out."