Chelsea are now in second place, four points behind leaders Arsenal, after staging a second-half comeback to beat Southampton 3-1 at Stamford Bridge on Sunday.
The west London club recovered after falling behind to Jay Rodriguez's opening goal just 15 seconds into the game and Blues manager Mourinho said their response highlighted the growing maturity of his team.
"It was a good performance collectively, and some good individual performances," said Mourinho, now in his second spell as Chelsea manager.
"It's the sign of a team that's going step by step, understanding my ideas and mentality, players progressing," the Portuguese added.
"Some of them, the ones that are not complete in my mentality or philosophy, adapting progressively, feeling the responsibility that Chelsea cannot be in December completely out of the title race.
"They must feel the responsibility to play for Chelsea and that was a sign just of maturity. Losing after 10 seconds, keep calm, let's go."
And he has challenged his players to build on their recent progress when they travel to face Sunderland and Stoke City in their next two games.
"I think my team is a team with a profile that I can't establish targets: to say I want to win five consecutive matches, or be top of the league.
"I want to work with them, feed the young players, feed the team. And, by the time we've done that, we're there.
"If you are 10 or 12 points behind, you are building but not fighting for the title.
"If you are three or four or five, you are evolving, building but also fighting for the title," Mourinho explained.
"The boys have to cope with the responsibility of being there. We have to be there. Now we have two away matches, teams who need points given the position they have."
Headers from Gary Cahill and John Terry overturned Southampton's lead before Demba Ba completed the victory in the final minute of added time.
"Demba played well against West Bromwich and really helped us to rescue a point and dominate in the last part of the game, and he was very aggressive in that push today (Sunday). Yes, I was very pleased with him."
And the manager refused to criticise Michael Essien, who marred his first Premier league start of the season with a misplaced back pass that allowed Rodriguez to score.
"Everybody makes a mistake. Strikers miss goals. Goalkeepers make mistakes. Midfielders lose balls, especially when they try to play. And he tried to play.
"It was a back-pass and they scored a goal. But I think he had a very normal performance.
"Essien is Essien. He's my man, Chelsea's man, no problem. Everybody makes mistakes."
Southampton's defeat was compounded by an injury to goalkeeper Artur Boruc, who suffered a suspected fracture.
"He's gone to hospital now for an X-ray, then we'll know what he's done to his hand or wrist," said Southampton manager Mauricio Pochettino.
The defeat at Stamford Bridge came after Pochettino's side had suffered a 2-0 loss at Arsenal.
But the manager believed his young side - who have so far exceeded expectations this season - would benefit from these reverses.
"We're always learning. We're the youngest team in the Premier League, so we'll learn over the course of the season.
"We won at Liverpool, drew at Manchester United, and have now lost at Arsenal and Chelsea, but we're still learning. We need to learn many things, for sure."