Three days after the impressive 4-0 Europa League win over Feyenoord, the manager made a mockery of that old adage: don't change a winning team.
Except, he did and this constant chopping and changing, of both shape and personnel, is hindering the team's search for a consistent run of form.
There were six changes to that side against West Ham, including the demotion of Wayne Rooney and Henrikh Mkhitaryan who both dropped to the bench after excellent performances in that match.
Mkhitaryan was so good on Thursday that it seemed impossible for Jose to overlook him but his performance still wasn't considered good enough for Mourinho to start him against West Ham.
He showed flashes of brilliance when he came on but should have been on from the beginning.
Matteo Darmian, who again look suspect defensively and offered little going forward, was recalled at left-back, with Jesse Lingard and Marcus Rashford also brought into the team.
He also reverted from the 4-3-3 used to such good effect against Feyenoord back to the more ponderous 4-2-3-1 used against the Hammers and we again missed the influence of 35-year-old Michael Carrick.
He sat out the match with West Ham through a minor injury and his absence led to the surprise recall - completely out of the blue - of German World Cup winner Bastian Schweinsteiger.
Mourinho's frequent chopping and changing was understandable and acceptable in the early months of his tenure.
He was still learning about his players, who should play where and tried different combinations to give his entire squad a chance to prove themselves - a natural process for any new manager.
But, nearly four months into the season and there's no indication that Jose is any further forward to finding a settled side.
If the manager himself is inconsistent with his team selections, then how can the players be expected to follow suit in their performances.
But what is particularly strange is that Mourinho has made a success out of being decisive in his illustrious career.
When he won the league at Chelsea, consistency was his side's trademark and he operated with a core eleven players which he only changed in the event of injury or suspension.
Tellingly, when we won the first four games of this season, we did so with an unchanged side.
The tempo and intensity was considerably slower that it was against Feyenoord and there seemed little logic in Mourinho shuffling his pack to such an extent.
One change, factoring in Carrick's enforced absence, would have sufficed.
Jose needs to decide on a settled side, and stick with it, if we are to be successful this season.