Thomas Tuchel is impressed the impact two 34-year-old strikers, Olivier Giroud and Edinson Cavani, are having this season on Chelsea and Manchester United respectively.
Giroud scored an acrobatic overhead kick in Chelsea's midweek 1-0 Champions League win away at Atletico Madrid. Meanwhile, Ole Gunnar Solskjaer is hoping Cavani will return from a minor injury to face the Blues at Stamford Bridge on Sunday.
That meeting could see the Uruguayan go up against his former manager at PSG in Tuchel, and the German spoke of how impressive both strikers are behind-the-scenes.
What did Tuchel say?
"Look at them when they switch shirts; they are totally fit. Their fitness is key. He has zero body fat, same as Edi," Tuchel said at his pre-match press conference.
"Edi is a player like Oli, who as a No 9 is always concerned about the team, will suffer for the team, always ready to sacrifice, always ready to do runs to open spaces. This is the characteristic of them both.
"Then in the box, they are both excellent finishers, they are experienced, they don’t get nervous and they both have composure. So they are both top quality strikers, top quality No 9s and for me their fitness and self-discipline is key to their success."
What's the bigger picture?
Fifth placed Chelsea are six points behind Man Utd, despite being unbeaten in Tuchel's first six Premier League games.
Both teams are locked in a battle to finish in the top four. Arguably, the teams all the way down to eleventh place are battling to qualify for Europe, and Tuchel didn't play down what this match represents.
"Hopefully, we can win. This is what we go for," he added. "We know that it is a big challenge because of their unbeaten away record so far. We know what we are up against a team that can hurt you any second with individual quality and can hurt you any second with speed.
"They are a strong team away, they can defend very compact and they are very, very good in transition with their wingers and with Rashford, Bruno Fernandes, Mason Greenwood, Edi Cavani, Martial and whoever plays it will be a big challenge to defend all this, to defend counter-attacks. The implication is huge.
"If we get a win out of this game, it is huge for us and if they get a win, it is huge for them to increase the difference between us. Let's see. We are very aware today was not a day where we focus absolutely.
"Today was the day to also bring the group together to train on the pitch and from tomorrow, we will be totally focused on this game."
Chelsea will also face Liverpool, Everton and Leeds in the next fortnight, which could have a huge impact on the end of season league standings.