With the scores tied at 2-2 Moses came on for Oscar in the 79th minute and gifted the homeside with the win after he rose to head home Mata's corner in the dying minute.
The game had hitherto been a ding-dong affair as Fernando Torres' 6th minute opener was cancelled out by Willian three minutes later.
Oscar then restored Chelsea's lead with a goal in the 40th minute, but Willian struck again for Shaktar to level the scores just two minutes into the resumption of the second half.
Moses appears to be in a rich vein of form as it should be recalled that he scored the opening goal in Chelsea's 1-1 draw with Swansea last weekend, making it two goals in his last two games for the reigning European champions.
The other Nigerian in Chelsea John Mikel Obi was also in action for the entire duration of the game.