The United striker, still only 21, pressed home his claims for a starting spot against France a week on Monday with a superbly-taken winner in the first half. After helping to hound Moussa Dembele out of possession, he raced onto a perfectly-timed through ball by Old Trafford colleague Ashley Young.
As Simon Mignolet advanced, Welbeck expertly lifted the calmest of left-footed finishes over his former Sunderland team-mate to the delight of the home crowd.
Young teed up Steven Gerrard for an opportunity that the Liverpool midfielder was unable to convert before Welbeck made way for Wayne Rooney eight minutes into the second half. Young was replaced by Jermain Defoe 13 minutes later and both sides hit the woodwork - Gillaume Gillet for Belgium and Defoe for the hosts.
Rooney produced a restrained but confident cameo performance, emphasising his authority with a relaxed header back to Joe Hart from the edge of the box. The striker, banned for the first two games of the tournament, took over the captain's armband for the final seven minutes when Gerrard was withdrawn.
Another United star, Nani, was also on the scoresheet for Portugal in their friendly with Turkey. The winger smashed a superb cross-shot past Volkan Demirel to reduce the deficit to 2-1 in the second half but the hosts' disappointing build-up to the finals continued with a 3-1 defeat.
Former Old Trafford idol Cristiano Ronaldo's penalty was saved by Demirel and things got worse as Turkey grabbed a third goal late on when Pepe put through his own net after Ricardo Costa's clearance