Managers use pre-season to their advantage for many things.
It's vital in getting a squad back in condition after the summer break and getting players ready for the new campaign. The tactical shape of a team is often worked on, and every so often, new systems are stumbled upon.
Whether it was Jose Mourinho's intention or not, the Chelsea manager has learned Cesc Fabregas has more strings to his bow in midfield and is capable of playing the deep-lying midfielder role expertly.
Indeed, from being an attacking midfielder who, at times, has been deployed as false nine in his career, Fabregas has had a look of a Xavi about him since arriving at Stamford Bridge.
And his impact has been significant.
With Fabregas alongside Nemanja Matic in the pivot of Chelsea's 4-2-3-1, the Spaniard has been the key to getting Chelsea moving on the front foot.
Where the inability of Ramires and others to turn over possession and start attacks at pace has been a hindrance for Chelsea, Fabregas appears to be the answer.
Against Ferencvaros on Sunday, the Blues had that 2013/14 look about them.
Facing inferior opposition in Budapest, they still failed to make their possession count in the first 45 minutes, struggling to bring Andre Schurrle, Oscar and Mohamed Salah into play effectively.
It meant the Ferencvaros defence wasn't stretched enough, they weren't put under sustained pressure and were able to keep their shape due to the Blues' pedestrian pace.
Introduced at the interval, Fabregas changed that.
The former Barcelona man dictated things from the middle. Matic mopped up, and Fabregas added the zip Chelsea had been lacking.
Within six minutes of him coming on, Chelsea had equalized through Ramires, cancelling out Zoltan Gera's first-half opener.
From there, Chelsea kept knocking on the door for a winner, with Fabregas threading the balls to feed their attackers.
As coincidence would have it, Fabregas scored the winner late on with a cool finish after a solo run through the heart of defence—just reward for an impressive display.
At other stages in pre-season, it's been a similar story. Fabregas has been the man who has kept Chelsea ticking over, allowing them to impact games further up the field in the way they couldn't last season.
Even in a 4-3-3, he's been the player who has impacted the flow considerably, assisting Diego Costa for his first Chelsea goal against Olimpija Ljubljana.
It was one thing buying a world-class striker in Costa, but with his compatriot also moving to west London this summer, the former Atletico Madrid man is going to get the service he needs to continue his fine goalscoring form.
Speaking to Chelsea magazine in August, Fabregas has hinted his role could well be more withdrawn this season.
"I know my place is in midfield—I want to play there and I think the coach knows that," he said.
"This is where I think I can give my best. It doesn't matter if I'm just in front of the defence or playing behind the strikers, they are the two positions I really enjoy."
Winning matches is what Mourinho enjoys most himself, and with Fabregas orchestrating things from midfield, Chelsea are going to take some stopping over the next 12 months.
Garry Hayes is Bleacher Report's lead Chelsea correspondent. Follow him on Twitter @garryhayes