Anthony Martial came off the bench to fire Manchester United to victory as Jose Mourinho's men edged a cagey encounter with high-flying Tottenham.
Second hosted third as the Premier League title contenders looked to keep up with early pace-setters Manchester City.
The match looked set to end in an unremarkable draw, only for substitute Martial to race onto Romelu Lukaku's flick-on late on to fire United to a 1-0 win against Mauricio Pochettino's Spurs.
The relief was palpable after the substitute's effort bobbled past Hugo Lloris in the 81st minute, continuing United's 100 per cent Premier League record at Old Trafford where they have not even conceded a goal.
A smattering of jeers had greeted Mourinho's decision to bring on Martial in place of Marcus Rashford, but the change paid dividends as United belatedly showed a cutting edge.
The substitute compounded Harry Kane-less Tottenham's shock Carabao Cup defeat to West Ham, but things could have been different had Dele Alli not wasted Spurs' best chance before Lukaku hit the post and Martial netted the winner.