The Red Devils face top-four chasing Tottenham Hotspur at Old Trafford on Sunday after losing to Arsenal in the FA Cup quarter-final last Monday.
United are currently in fourth place but face pressure from Liverpool, Southampton and Spurs for the final Champions League qualifying spot.
Sinclair sympathised with United supporters after an unconvincing couple of months in the Premier League, highlighting United’s “lack of identity”.
Sinclair told BBC Sport:
United are two points ahead of their nearest rivals Liverpool ahead of the visit of Mauricio Pochettino’s side.
The League Cup runners-up can move level on points with the 20-time English champions if Spurs beat Louis van Gaal’s side.
Spurs were 2-1 winners at Theatre of Dreams last season thanks to goals from midfielder Christian Eriksen and former City striker Emmanuel Adebayor.
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