The 29-year-old, a regular goalscorer since joining the U's in 2008, suffered a chipped bone in his foot earlier in the season but is now fully recovered and netted in Tuesday night's JPT loss against Portsmouth at the Kassam Stadium.
That defeat continued a poor run of form at home for the U's but Constable was in upbeat mood afterwards.
"It's the best we've played here this season," Constable told BBC Oxford.
"I just hope we go into Saturday's game [with Northampton] full of confidence after our first-half display."
Oxford and Northampton meet for the 21st time this weekend with Town just shading the encounters by 10 wins to 9. Both of last season's games went the way of the respective home side.
Source: Cobblers Mad