The defending champions were knocked out in the group stage of this year's competition before entering the Europa League.
The Blues have since gone on to reach the semi-finals of that tournament, where they will face Basel in the second leg of their encounter on Thursday.
"Chelsea is a club which deserves to be in the Champions League every season," Mata is quoted as saying by The AP.
"We are in third position, we have four games to go, against the likes of Manchester United and Tottenham, and I think we can [qualify]."
Chelsea will take a 2-1 first-leg lead into Thursday's Europa League semi-final second leg against Basel at Stamford Bridge.