Promoted Chesterfield edged another point closer to the League Two title with a 0-0 draw at Oxford.
The Spireites now know that victory against Bury at the B2net Stadium on Monday will bring them the championship.
The hosts' plans were thrown into disarray as they lost two centre halves through injury.
Jimmy Sangare, on his home debut, hobbled off with a foot injury just before half-time.
And his replacement, Mitch Hanson, lasted only 12 minutes before he was stretchered off following a clash of heads.
Oxford striker Alfie Potter missed two good chances in the second half, and James Constable was denied by a fine save from Lee. Spireites skipper Dwayne Mattis made two brilliant blocks to ensure a clean sheet, as the Chesterfield fans' celebrations continued.