A damaging 2-1 loss at London rivals West Ham on Sunday represented a fifth defeat in six Premier League games.
Mourinho has never endured such a poor six-game sequence during his decorated career and Spurs are now ninth in the table having looked like title contenders earlier in the campaign.
The home Europa League last-32 second leg against Wolfsberger on Wednesday – a tie Spurs lead 4-1 – is likely to offer some brief respite to Mourinho.
"I am not happy, but maturity helps, and I am feeling very confident," Mourinho told reporters on Tuesday.
"I believe that we will win through and that I will be in Tottenham's history through good reasons rather than bad.