Speaking after a perfunctory win over Anderlecht in the group opener in the Champions League, Mourinho, when asked about the lowly 29 575 attendence, said: "We have had two consecutive home matches and our supporters are not that rich.
"The opera, the theatre, the football are all expensive, but our crowd were fantastic all night."
Chelsea's capacity is close to 44,000.
The cheapest ticket last night was £35.
Frank Lampard said: "It's a lot to ask of people to keep spending money," said Lampard.
"At this stage of the season you see a lot of grounds that are not always completely full.
"Our stadium wasn't full but the fans that were here had a right go at getting behind us."