Wilfried Zaha scored his first U21 goal with a superb individual effort, while substitutes Jack Robinson and Nathan Delfouneso were also on target against the Romanians at Wycombe's Adams Park.
Zaha, who has been loaned back to Crystal Palace after joining Manchester United, was named man-of-the-match and Eastick acknowledged his efforts.
When asked about the exciting youngster, Eastick said: "He is a very talented player and everybody knows that.
"Obviously playing up front again tonight like he did against Sweden has given us another option.
"I thought the front three players and Jonjo Shelvey playing in behind them were very fluent tonight.
"Even though Romania had 10 or 11 players behind the ball, we caused them quite a few problems."
Zaha usually operates as a winger for Palace, but he played as a lone frontman for England and Eastick feels he embraced this role.
"He plays wide for Crystal Palace and it is slightly different role we are asking him to do," he said.
"Obviously in terms of international football, you need that flexibility. We don't want to be too mechanic, too robotic when we have possession of the ball.
"Having someone like Wilfried helps as he can play wide and he showed tonight can be really effective in those forward areas.
"I thought Jonjo Shelvey's performance tonight was really outstanding.
"I though when Wilfried came short into those pockets of space, Jonjo picked his timing of the runs really well and the movement from those two players was excellent.
"And of course the wide players were excellent as well so it has certainly given Stuart some options for Monday and also for the finals."
Reflecting on the win, he added: "It was comfortable. I thought we played some really excellent football.
"Sometimes when teams bank up against you like that, it is not always easy. But I thought some of the quality of football was outstanding and it was a very pleasing performance."