That is the verdict of former Arsenal player Paul Mariner.
Torreira had to bide his time with appearances from the bench in the north London outfit’s first five Premier League games.
But he has played every minute of their last six with the Gunners currently on a 15-game unbeaten streak in all competitions.
Uruguayan star Torreira – a £26million purchase from Sampdoria – has proven a key addition for Emery with the Spanish coach having shown signs of steering Arsenal into the right direction.
Such is their current form, optimism around the club is rising over a potential Champions League return having missed out on the top four in both of the last two seasons under predecessor Arsene Wenger.
Torreira’s combative performances in the middle have been crucial to Arsenal’s improvement and though the entire team as a whole have improved, particularly going forward with the club having produced several goal of the season contenders already, he attributes Torreira as the main factor.
Arsenal stretched their unbeaten run with a goalless home draw against Sporting Lisbon last night at the Emirates Stadium as Danny Welbeck’s nasty ankle injury overshadowed the evening.
But Emery’s men at least sealed their progression to the knockout phase of the European competition – which also offers an alternative route into the Champions League for the team that wins it.
On whether Arsenal can do so rather than rely on a domestic finish, Mariner told ESPN FC: “Depends who drops out of the Champions League.
“I was waiting for the Liverpool game [to judge Arsenal’s improvement], I wanted to see what they brought to the table.
“I must admit Torreira – the holding midfield player – has almost as a single guy transformed this team.
“He’s pushed Granit Xhaka further up the park a little bit where he’s a bit better, the protection for the back four is good.
“Can they win the Europa League? It’s a big ask but at the present moment in time, no I don’t think they can.”
Torreira himself is confident that an improved Arsenal can aim for the Champions League having been virtually written off in the top four race at the start of the season.
The 22-year-old told Sky Sports: “ ”I really hope that we can achieve some really big goals this season. We are obviously competing in four competitions, so really it’s a case of so far so good.
“We’ve had a very good run so far, that has taken a lot of hard work but the team is working hard and improving with each game.
“Personally, I think a good objective for us would be to try and qualify for the Champions League, that would be fantastic for the club and the fans.
“We also want to fight until the end in the Premier League, the Europa League, Carabao Cup and when the FA Cup starts too.”