Bruno Fernandes looked to be sending United to its seventh straight away win when he scored in the 79th minute, moving onto 10 goals in his first full season in the league.
Defensive midfielder McTominay — who hadn't scored in the EPL since March — netted in the second and third minutes after he was left plenty of space.
Vardy, 31, went from playing amateur football to being a Premier League winner with Leicester City in the 2015-16 season before an England call-up followed.
Vardy, who scored 24 goals in Leicester's unlikely title triumph in the 2015/16 season, said a united dressing room was a key factor in building a successful team.
Lorenzo Insigne's penalty three minutes from time denied England another impressive World Cup warm-up friendly after Vardy scored earlier.
Salah was again instrumental for Jurgen Klopp's side as he took his tally to 17 Premier League goals this season with two fine finishes.
City goalkeeper Bravo saved Mahrez and Vardy spot kicks for the decisive moment following a 1-1 draw after regulation and extra time.
It was a third loss in its last five league games for Tottenham, which has slumped 13 points behind first-place Manchester City, having played a game more.
Drinkwater was accused of letting down England boss Southgate last week when he pulled out of the squad for the friendlies.
With only its second away win of a dismal title defense, Leicester moved nine points clear of the bottom three with four matches remaining.
Leicester lacked a cutting edge and it was Boro who came closest to taking all three points at the Riverside Stadium.