Juan Mata says that the Chelsea dressing room has always been "united" behind the manager, André Villas-Boas, and the midfielder believes that the club is back in the Premier League title race, after Monday's morale-boosting 2-1 home win over Manchester City.

Villas-Boas has cut an embattled figure in recent weeks, as he has seethed under the weight of criticism and been forced to contend with talk of disharmony in the ranks. The Portuguese has constructed something of a siege mentality and, after the decisive 3-0 Champions League victory over Valencia at Stamford Bridge last Tuesday, he claimed to have given the club's critics a "slap in the face".

The triumph over City, when the team recovered from the concession of an early goal to snatch the points through Frank Lampard's late penalty, showed the character in the squad and, according to Mata, reinforced the point that everybody was with Villas-Boas.

"The team has shown in the worst moments that we are united behind the manager," Mata said. "Now that we are in a run of results where things are more positive, everything is easier, but we have shown that we are together with the manager and the technical staff, like a family.

"The manager wants everyone to feel involved, and feel ready to produce the goods, and that is what we have now. There are lots of players here but we all feel like a part of things."

Chelsea have now won three straight matches – the first in the sequence was the 3-0 success at Newcastle United – to sit third in the Premier League, seven points behind the leaders City, and to qualify for the Champions League last 16. Previously, they had lost five of nine games in all competitions.

"We showed our character when we went behind to City," Mata said. "We could have really dropped down but we didn't lose any fight. We managed to turn around the game against the league leaders and a team who had not lost a game before this season. That gives us a lot of belief.

"We have won three vital games, which has broken the negative run we were in and now we can hopefully start a good sequence to keep on rising up the table. We have to keep fighting to win games because we are still in with a chance of a lot of trophies.

"The most important thing in football, in any sport, is confidence. A few days ago, we did not have as much confidence as we do now, and that can only be attributed to results. We can keep growing and growing in confidence."

Mata, the £23.5m summer signing from Valencia, who has made such an impressive start to his Chelsea career, also paid a glowing tribute to Lampard, who no longer feels like an automatic selection. Lampard is far from happy at his demotion by Villas-Boas and he struggled to conceal his frustrations after his winning goal on Monday.

"Lampard is a legend here, a legend who keeps on providing a lot of good to the club," Mata said. "He is a great presence to have in the dressing room and for me, he is a standard-bearer for the entire world of football. I have only known him a few months but he is a great guy and he has been very accommodating to all the new players coming in.

"He has the experience to remain calm even when he's not playing, to know that there will be times when he will play because there are so many games. He still has a lot to give. He will score a lot of goals and play a lot of games this season, I'm sure."