PLZEN, Czech Republic, Dec 12 (Reuters) - Manchester United ( MANU ) learnt lessons from their bland first half at Viktoria Plzen in the Europa League on Thursday and sped up the action in the second period, allowing them to get a 2-1 win, coach Ruben Amorim said.

Forward Rasmus Hojlund scored twice in the second half to allow United to come back from a goal down at six-times Czech champions Plzen for their third consecutive European win.

"We improved during the game," Amorim told TNT Sports. "We controlled the game in the first half but without any great chances.

"We lacked speed and movement and we didn't control the ball because the pitch was difficult to make the connections with the strikers. Viktoria didn't have chances either.

"In the second half, we gave a goal away but we reacted well. We pushed the opponents to their own half and we managed to score. The win is important at the moment and it's good to prepare for the next game."

United, still unbeaten in this year's competition, had more possession throughout the game but had to stand up to an initial spell of pressure from the hosts, who ended up taking the lead in the 48th minute through forward Matej Vydra.

"The speed improved (in the second half)," Amorim added. "I told the players we need more movement in front because they have to feel we are a danger.

"We changed a little bit of our game and the players from the bench also helped. We improved not just the way we play, but also the speed of the game.

"We are improving in some details. We controlled the transitions very well. We were aggressive when we lost the ball. We need to spend more time near the opposition goal."

The Portuguese manager was happy with the performance of substitute Hojlund, who needed just six minutes to cancel out Plzen's opener before sealing the win with another strike just before fulltime.

"He is improving, he is more near the goal now," Amorim added.

"He knows better the movement he has to do. He could score more this evening. But he is scoring, working and controlling the ball better."

The Danish striker has been involved in six out of 12 of United's goals in the Europa League this season, scoring five of them.