The Gunners put in an impressive performance as they won at Old Trafford in the league for the first time since 2006.
Pierre-Emerick Aubameyang’s second half penalty was enough to wrap up all three points and move Mikel Arteta’s side to within one point of the top four.
The Gunners have previously struggled in big away games, but seem to have turned a corner under the Spanish boss.
The win over United ended a run of 29 games without a victory against the ‘top six’ away from home, and Leno highlighted the massive strides forward the north London club have taken.
‘First of all it was a very important win for us when you look at the table,’ goalkeeper Leno told the club’s official website.
‘It’s been a long time since we won away against a team from the big six, and as well at Old Trafford. It’s been 14 years I think, so too long but finally we’ve done the job.
‘It was a very collective, strong performance from us. Our players were brilliant and I think everybody had the right attitude and mentality to win. It was very hard for Man United to create chances.
‘At the end of the day, this is the key. The collective performance and defensive work were really important tonight and I think we’ve worked on that. You can already see that it’s much more impressive than it was one or two years ago.’
‘It’s a long, long process and we still have a lot of work ahead of us,’ the German added. ‘We need consistency. This season we’ve had a lot of good games but also some games where we could have done better. We’ll keep working on that though.
‘We’re all doing a great job and the most important thing is that we stay grounded, we know where we come from and hopefully it goes in the same direction.’