Recce James
Manchester United players celebrate with Reece James after he scored against LA Galaxy.Reuters

Manchester United entered into a new era under Louis van Gaal with an emphatic 7-0 hammering of Major League Soccer (MLS) side Los Angeles Galaxy in California on Wednesday night.

Ashley Young, Reece James and Wayne Rooney all scored a brace, while Luke Shaw and Ander Herrera made their debuts in the famous red shirt for United in front of 86,432 spectators at the Pasadena Rose Bowl.

Van Gaal was determined to make a strong start in his first match as United manager and fielded a strong lineup against the MLS side, which is fourth in the Western Conference standings.

Rooney, Shaw, Juan Mata, David De Gea and Danny Welbeck all featured in the first half as the Premier League side, playing in a 3-4-3 formation, took a 3-0 lead in the first 45 minutes.

The Red Devils dominated the match from start and Herrera, who joined United from Athletic Bilbao in the summer and was the most impressive player on the pitch, took the first shot on goal in the fifth minute but was denied by goalkeeper Jaime Penedo.

The visitors opened scoring in the 13th minute when Danny Welbeck scored off Mata's pass with the ball whistling into the bottom left corner. Mata, playing in a front three with Welbeck and Rooney, created problems for Galaxy with his precise passing and sharp movements.

The home team displayed poor defending and gave away penalty off a handball from Leonardo and Rooney made no mistake in putting the ball past Penedo.

Rooney completed his brace moments later, when Tommy Meyer made a defensive error and the English striker score off a rebound.

Van Gaal made nine changes in the second half, as just Fletcher, who was wearing the captain's armband, and Herrera remained on the pitch, while Tyler Blackett, Michael Keane and Reece James, to name a few, came in.

United were already certain to win the contest after their dominating first half performance but van Gaal's men pressed for more goals in the second. James scored midway into the second half on a weighted cross from Young to make it 4-0.

The youngster doubled his tally in the 85th minute, when Herrera gave a beautiful through ball to Young but Penedo saved the shot and the ball went straight to James, who made no mistake in completing a brace.

Young, who missed a scoring opportunity minutes before, scored twice in the final moments to script a memorable debut for van Gaal in United colours.

The Red Devils will face Italian side AS Roma, who defeated Liverpool 1-0 in their preseason friendly, on Saturday in Denver.

Manchester United - First Half (3-4-3): David De Gea, Chris Smalling, Phil Jones, Jonny Evans, Antonio Valencia, Darren Fletcher, Ander Herrera, Luke Shaw, Juan Mata, Wayne Rooney and Danny Welbeck.

Second-half - (5-3-2): Anders Lindegaard, Rafael, Michael Keane, Darren Fletcher, Tyler Blackett, Reece James, Ander Herrera, Tom Cleverley, Shinji Kagawa, Ashley Young and Nani.

Watch the highlights of Los Angeles Galaxy vs Manchester United