James slotted straight back into the side in his favoured right-wing back position and the boss expressed his pride of his performance, in what was a physically challenging and demanding game.
"Reecey comes in after eight weeks of injury and plays almost in our level," explained Tuchel. "I am proud, I have to say. We're in a good way.
"It was a bit rough for us but since we came back from Abu Dhabi. We had a tight game against Crystal Palace, trained very well after. Played a good match against Lille, trained even better after. I feel the group growing and it proved it in this game.
"We're coming back. We got quality back today with Reece who made a huge impact for us and we're in good shape."
Tuchel also praised the performance of the returning Chalobah, who was strong throughout the Wembley contest alongside Thiago Silva and Toni Rudiger in defence as they kept Liverpool's front three quiet. Andreas Christensen missed the game with an achilles problem.
"Trevoh Chalobah did not play for six to eight weeks, and he just played 120 minutes against Diaz, Mane and Salah," Tuchel told the club's website. "And he was brilliant too."