The fit-again midfielder has made substitute appearances against West Ham and Manchester United after missing five weeks with ankle and hip injuries.
It was put to Mousa that it must have been frustrating to miss out on high-profile matches against the likes of Real Madrid and Liverpool in recent weeks.
“It’s been tough, of course,” he said. “It’s frustrating not only missing the big games but you just want to play.
“I can’t get too carried away because of the result but I played half-an-hour against Manchester United and that’s positive for my physical condition.
“I thought I started well this season so the injuries have been frustrating but the team has been doing well. Of course, the results against United and West Ham were disappointing but I don’t think we need to worry too much. We’re playing well.”
Mousa missed our 1-1 draw against Real Madrid at the Berbabeu and would love to play his part as we take on the holders in the Champions League at Wembley on Wednesday night.
“I want to play as much as possible and it would be good to play against them,” added Mousa, who recently passed the 200-game milestone for us. “We showed over there that we can compete.”
We’re level at the top of Group H with Real Madrid ahead of this week’s fixtures. Borussia Dortmund host APOEL.