Eric Bailly left the stadium on crutches and wearing a knee brace on his left leg after suffering an injury just nine minutes after coming on as a second-half substitute.
Victory makes it four wins from four pre-season games for United. "We need to get back to Manchester and do the scans but let's hope for the best".
A lively start to the match saw United come closest, as Martial struck the upright following a fine burst of pace from Daniel James in midfield.
The game seemed destined for penalties until 18-year-old Gomes beat two defenders inside the penalty area and fired home.
There were plenty more encouraging signs here for Ole Gunnar Solskjaer, who appears to have vanquished the ghosts of last season and restored the feel-good factor at United.
A goal by Anthony Martial at the 21st minute opened the score for Solskjaer's men, as Martial's combination of a tight angle and a really strong hit made it hard for goalkeeper Gazzaniga to do much about it.
Attacking midfielder Alli, perhaps frustrated after missing a golden chance, was booked on 12 minutes after a second late challenge in front of a full house.
There has been a style, and at times a swagger, about United, who also have benefited from an on-form Paul Pogba as, despite his well-publicised comments about a summer move, the France worldwide has knuckled down.
Following the match, Spurs' Argentinian boss Pochettino issued an apology on behalf of his team to Manchester United and offered an explanation as to why the fixture devolved into such a hot-tempered affair. Young Spurs defender Japhet Tanganga was yellow-carded too.
The win made it a satisfying four wins in succession for Solskjaer's men, who head to Norway next week to play the Norwegian's hometown club, Kristiansund, and then to Cardiff for a contest with AC Milan.
"We've had six centre-backs rotating here and all done well", he said.