Arsenal manager Mikel Arteta believes his team has made a lot of progress.
The Gunners may be mid table in the Premier League, but they are excelling in the Europa League at the moment.
Arsenal defeated Olympiacos 3-1 away from home in the round of 16 first leg on Thursday.
Asked about the team's progress, Arteta told reporters: "I have been saying that fro a while, and I can probably see more things because internally I know the process that has happened and how much has happened since we were here a year ago.
"I think the difference is really big and we are really pleased with the result and the goals that we scored, and the way that we played in big moments in the game.
"But as well we have to be very clear and honest with ourselves that we gave three goals to the opponent and they took one, and at that level they are going to punish you.
"So to go to the next level, we haver to stop doing that and be more ruthless - and when you are that dominant and playing that well, just kill the game."
