Romelu Lukaku of Manchester United scores their second goal during the Premier League match between Swansea City and Manchester United at Liberty Stadium on August 19, 2017 in Swansea, Wales.

Anthony Martial of Manchester United scores his sides fourth goal during the Premier League match between Swansea City and Manchester United at Liberty Stadium on August 19, 2017 in Swansea, Wales.

Romelu Lukaku of Manchester United celebrates scoring his sides second goal with Daley Blind of Manchester United during the Premier League match between Swansea City and Manchester United at Liberty Stadium on August 19, 2017 in...More

Martin Olsson of Swansea City controls the ball during the Premier League match between Swansea City and Manchester United at Liberty Stadium on August 19, 2017 in Swansea, Wales.

Paul Pogba of Manchester United celebrates after the Premier League match between Swansea City and Manchester United at Liberty Stadium on August 19, 2017 in Swansea, Wales.

Anthony Martial of Manchester United celebrates scoring their fourth goal during the Premier League match between Swansea City and Manchester United at Liberty Stadium on August 19, 2017 in Swansea, Wales.

Romelu Lukaku of Manchester United celebrates scoring their secondr goal during the Premier League match between Swansea City and Manchester United at Liberty Stadium on August 19, 2017 in Swansea, Wales.

Paul Pogba of Manchester United celebrates scoring their third goal during the Premier League match between Swansea City and Manchester United at Liberty Stadium on August 19, 2017 in Swansea, Wales.

Romelu Lukaku of Manchester United scores their second goal during the Premier League match between Swansea City and Manchester United at Liberty Stadium on August 19, 2017 in Swansea, Wales.