Jesse Lingard says there is a real togetherness within the Manchester United squad at present.
United are fighting on four fronts, having reached the EFL Cup final in midweek and the fifth round of the FA Cup on Sunday, while they face Saint Etienne in the Europa League round of 32 in February, sitting sixth in the Premier League.
Speaking with Sky Sports News HQ, Lingard insists the squad are full of confidence having lost just one game since October, adding that the club are "on a roll".
"The lads and everyone are very confident at the moment," said the 24-year-old. "Everyone is on a roll at the moment.
"It's the team spirit, winning matches, there's a real togetherness in the squad, we've really gelled in the last three or four months.
"Everyone speaks to everyone, we've really come together, and starting to show it on the field too."
Lingard has played 20 times this season under Mourinho, scoring three times, having played 40 times under Louis van Gaal last term.
And the youngster says the United squad are still trying to impress the Portuguese manager in training.
"He's still the same, he's laidback, but when things aren't going his way obviously he'll tell you. The lads are still trying to impress him, and still get a feel for it," Lingard said.
"The squad is coming together, the manager is coming together, and it's a great feeling at the moment.
"We've got the strength in depth to rotate. Everybody works so hard on the training pitch and then obviously it is down to the manager to rotate.
"But as long as you work hard, you're patient, and when your chance comes, don't disappoint and perform."
Lingard added that United have the squad to go strong in the cup competitions this season, with 14 points separating them and leaders Chelsea in the Premier League, meaning a title charge is unlikely.
"We're still in four competitions, so everybody is going to play.
"I all competitions are still tight, with that we'll take every game as it comes, and we're still in a good line for the three competitions.
"The squad we've got at the moment, the confidence and the run we're on, nobody can beat us, and it's definitely possible (to go all the way in the three competitions)."