Liam Trotter, Pablo Counago and Owen Garvan scored the goals as the reserves ran out comfortable winners at Luton.
Trotter gave Town the lead on 17 minutes when he finished off a good move involving Counago and Colin Healy.
Luton responded against the run of play with Marek Nwokeji equalising five minutes before the break.
Blues wasted several good chances to extend the lead before Counago put Town ahead from the penalty spot on 70 minutes after Ed Upson's shot had been handled.
Garvan completed the scoring with a fantastic strike 10 minutes from time, lashing in a 20 yarder following a corner.
"It was a good performance, we passed and moved the ball around well and should have won by more," reserve team boss Bryan Klug told the Club website.
"If there was a criticism, it was that we should have had more goals but the approach play was very good."