Mourinho's Premier League champions slipped to their sixth defeat of the campaign on Saturday as Liverpool ran out 3-1 winners at Stamford Bridge.
The reverse leaves the Blues 15th in the table and the defeat to Jurgen Klopp's resurgent Reds was Chelsea's ninth in 17 games in all competitions.
Mourinho was in prickly mood after the game and Chelsea are now a whopping 14 points behind league leaders Manchester City, who extended their advantage with a 2-1 win over Norwich City on Saturday.
The Chelsea boss has used a litany of excuses and diversionary tactics in his post-match media dealings this term to try and mask his side's failings, but the reality is that neither he nor his squad have been anywhere near the required standard for a team with designs on recording their second successive title this term.
Redknapp watched the defeat against Liverpool as an analyst for BT Sport and the former QPR and Tottenham boss thinks that it is time for Mourinho to reaffirm himself as one of the planet's elite coaches.
Redknapp said: "He can blame anyone he wants for the defeat but it was a poor performance today from his side. You only have to see what he is going through, and when you're a manager you're going to lose games, but he is not used to it.
"He's not used to losing so many games, and he's got praise for what he did last season but now he's had to take some stick and criticism and he is finding it very hard to handle.
"It's happening on a weekly basis and he is finding difficult. He's not used to it at all, but he has to show what he is made of now and turn it around."
Chelsea return to action on Wednesday when they take on Dynamo Kiev in the Champions League before a visit to Stoke City on November 7.