We fell to a 4-1 defeat against table-toppers West Ham United at London Colney on Saturday afternoon.
Jack Wilshere's side, who were looking to bounce back from last week's narrow defeat to Southampton, started the brighter of the two sides and had the game's first real chance through Osman Kamara, who sent his effort wide after impressive work from Myles Lewis-Skelly.
The visitors found a foothold midway through the half and took the lead courtesy of Mubama, the forward charging down Alex Kovacevic's kick to roll the ball into an empty net.
West Ham's lead was doubled just moments later, Kovacevic misjudging the flight of a corner and leaving George Earthy free to head home unchallenged.
Mubama completed his brace on the stroke of the break, firing his header beyond Kovacevic to make Wilshere's half-time team talk an even more important one.
We came out strong after the interval and almost pulled one back through Ethan Nwaneri, our midfielder cutting inside and firing his effort just wide of the post.
Lewis-Skelly continued to impress in the engine room and our spirit was rewarded with a goal 15 minutes from time, Mathaeus Roberts firing in from close range after the visitors failed to clear their lines.
We committed to more attacks in search of a second in the closing stage, but conceded a fourth deep into stoppage time, Favour Fawunmi killing all hope of a comeback and securing all three points for the visitors.
WHAT IT MEANS
We drop down to ninth place in the Under-18 Premier League table after nine matches played.
We'll look to get back to winning ways next weekend, when we return to Under-18 Premier League action away to Leicester City on Saturday, December 3.
Kick-off at the Leicester City training ground is at 11.30am (UK).
Starting XI: Kovacevic, Small, Robinson, Brown, Quesada-Thorn, Lewis-Skelly, Oulad M’Hand, Ferdinand, Nwaneri, Kamara, Green
Substitutes: Gower (for Small, 46), Roberts (for Green, 64), Dudziak (for Oulad M’Hand, 75), Ryan (for Kamara, 85). Not used: Rojas
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