Manchester United recorded their biggest Old Trafford win over Chelsea since 1965 to condemn Frank Lampard to a miserable start as a Premier League manager.
Marcus Rashford scored twice, either side of a close-range effort from Anthony Martial, who had been given the number nine shirt back following the sale of Romelu Lukaku to Inter Milan.
Substitute Daniel James completed the scoring with a goal on his debut nine minutes from time.
Manchester United goalscorer Marcus Rashford, speaking to Sky Sports: "It was a good start, in the first half we could have been a bit sharper but it is to be expected in the first game. In the second half we looked sharper and the fitness work we have been doing over the summer pulled us through."
On playing on the left of central striker Anthony Martial today: "It gives us fluidity, Anthony can play both positions, it gives us more options. Defensively it can be tough but we will get better.
"Whether I'm there or more central, is the same really, just more defensive duties on the left. But as time goes on we will get better at it. It's looking good but we've still got a lot to work on."
On confidently converting the penalty for United's first goal: "It's about waiting for the keeper but if he doesn't give you much then you go with which side you're confident with. The keeper stood tall so it was hard. I look at him and wait to see if he can give me some movement when I'm running up and then decide which side I'm going.
On United's style of play: "We're playing to our strengths, we've had players to be good on counter attack, some times decision-making has let us down, but a lot of us are young players so need to keep working on that."
Courtesy of Sky Sports.
Other Premier League Results:
Leicester City 0 Wolves 0.
Newcastle United 0 Arsenal 1.