Despite an imposing 2-0 away triumph following goals from Yoan Gouffran and substitute DeAndre Yedlin, the Newcastle boss believes his team will get better.
"We had more control in the first half and scored a goal which made it easier in that we knew what we had to do and in the second they were pushing and pushing so it has been a tough game against a good team," the Spaniard said.
"The main thing for me has been to see the team working as a team from the strikers to the 'keeper and also the players coming from the bench so that is a positive thing for the future.
"But I still think there is plenty of room for improvement, my feeling is the team is doing well but still we have things we can improve on.
"The commitment is there, they listen to us so that is why we have to be positive and confident for the future because the team knows what we are trying to do and work very hard.
"We can improve in a lot of areas, in defence, in the middle, and in attack and the way we play the counter-attacks but after that I am really pleased with the team and the way they work but they know, we know, we can play better."