The Blues have struggled to keep clean sheets this season, but have improved recently keeping three in their previous four Premier League games.
And Villas-Boas was keen to point out this fact, as well as stating that it doesn't matter what people say about the team as long as they get results after Didier Drogba's double inspired them to top spot in Group E.
"To be fair, in the Premier League games we have kept three clean sheets in four games so our defence is not that bad," he told Sky Sports.
"We have been improving a lot. There has been a lot of criticism of our players and I think they gave everyone a slap in the face today.
"It really doesn’t matter what they [the critics] say about me, it matters that Chelsea finishes top of the group and manages to obtain the objectives that we set out to get.
"We managed to qualify in first position and we wait for the draw to see how far we can go in the competition.
"In terms of the result, I’m very happy for the players. They worked very hard for this win. We managed to get a result that made us proud at half-time, and guess what, we have finished top of the group against all odds.
"It was good to score straight away. Valencia started a bit uncomfortably, they lost possession a couple of times. We were available for transitions after that and we scored from one of them.
"Our strategy was always to keep our line of defence near to our goal, and we managed to get a fantastic result and finish top of our group."
The Portuguese boss was also in a positive mood about the upcoming visit of Manchester City to Stamford Bridge, a team that has scored in every game this season bar one - against Bayern Munich.
Villas-Boas added: "It’s a very good emotional bonus that will help us recover physically for the game against Manchester City, which is very important.
"I don’t know what is going to happen on Monday night but we have a chance to maybe shorten the distance between us and the leaders.
"They are a very competent and excellent team. We have that chance; it is going to be difficult, but it is in our hands as well.
"If we manage to do that, we bring the Premier League alive. If not, things will be difficult for us, but there are more December fixtures where we can pick up points."