Liam, son of former striker Leroy, played in defence to help the side keep a clean sheet, and Roger says: "He played at right back but can also play on the right of midfield. He did well and is very skilful."
Liam can play another reserve game for the Hammers before returning to his club Bristol City, but Roger says no decision has yet been made on whether to put in a bid for him.
"It hasn't gone that far yet," he says, "and we will just have to wait and see what progresses."
Another player to earn the plaudits was Richard Garcia, who scored the goal of the night and Roger adds: "It was the third, killer goal - and it was fantastic.
"Omer Riza made the run, played Richard in, and he drove it in from a tight angle at a distance of 23 or 24 yards at the near post.
"He is making solid progress and we are pleased with him. It is important he plays well in the reserves because that is where the first team manager sees him, and he has a good attitude."
Riza also scored two goals to press his claims, and Roger adds: "He was always making runs and was alive. He was a real menace and, although he has missed chances on occasions, he took them well tonight and all his good work paid off.
"Apart from the disappointments against Arsenal and Fulham, which were the only two games we have deserved to lose, we are doing okay."
Titi Camara was rested for the game but will play in a behind closed doors friendly against Leyton Orient this week, while Shaka Hislop, who wasn't on the bench on Saturday because of international duty with Trinidad & Tobago, is still away.
Laurent Courtois scored West Ham's other goal.
Team: Andersson, Rosenior, Minto, Garcia, Foxe, Soma, Newton, McCann, Todorov, Riza, Courtois. Subs unused: Johnson, Jackson, Ferrante, U'ddin, Britton.