The wet weather which has blighted Coventry for the last few days, meant that the planned Family Fun Day had to be cancelled but the pitch was in perfect condition and the game was never in doubt.
Sphinx got off to a bad start when a through ball was played for Lewis Dodd to run and stick out a leg to deflect the ball past Chris Daffern with only two and a half minutes gone.
Paul Charnley's side were closed down in midfield by the visitors who increased their lead in the 31st minute. A free kick was sent to the back post and headed across the goal for Danny Haynes to bundle over the line.
It was all going wrong for Sphinx. Defender Dave Care was being treated for a hamstring injury after being shoved to the ground in the 34th minute and Coalville made the most of the power play by adding a third goal. Michael Swan was the goalscorer heading home from a James Dodd free kick.
Adie Fisher replaced Care and Sphinx started to get back into the match against a side which was third in the table going into the game.
Robbie Stevenson shaded a post with a 52nd minute free kick and it was eleven minutes later before Sphinx had their first shot on target in the match when Callum Woodward had a drive saved by Chris Gibson.
Woodward was replaced by new boy Tom Thacker in the 66th minute. It was Thacker who pulled one back for Sphinx in the 90th minute with a header but by then, the heart had gone out of the game following an 88th minute injury to keeper Chris Daffern who had to be carried off with what looked like a hamstring injury.
Sphinx now go to Oadby Town on Tuesday night.
Sphinx Reserves game at Highgate United was postponed last night.