The young midfielder entered the action alongside Spurs team-mate Adam Smith in the 75th minute at Adams Park.
Danny Rose started and played the first half as England dominated and stretched their winning streak to eight matches. Romania caused a few problems in the early exchanges but it was one-way traffic for most of the game.
Danny had a decent strike at goal saved by Romania goalkeeper Laurentiu Branescu before Wilfried Saha opened the scoring in the 34th minute.
Jack Robinson doubled the lead on 62 minutes from Jonjo Shelvey's cross.
As expected, Tom got on the ball at every opportunity on his arrival and the Spurs pair combined impressively to open up the visitors' defence, Tom's pass between centre-back and full-back released Adam to the byline, but his cutback just evaded Nathan Delfouneso.
Tom hit a stinging volley straight at Branescu before Delfouneso completed the scoing in the last minute, tapping home from Shelvey's free-kick.
The Under-21s now switch Wycombe for Brighton and a final friendly against Austria on Tuesday before Stuart Pearce names his squad for this summer's European U21 Championship in Israel.