Although it was only pre-season, the sight of Nemanja Matic tearing around the pitch was enough to frighten any watchers from rival Premier League clubs who had made the effort to watch Chelsea in action against Real Sociedad earlier this month.
Of course, their 2-0 win over the Spanish side just before the start of the Premier League season didn't mean much at face value; it was a run-out to blow off the cobwebs before the real action started. Only one player in Blue made it all the way through the game without being subbed, and that was Thibaut Courtois in goal.
However it was hard to shake the feeling that the game was Jose Mourinho flexing his muscles, or even showing his hand. He'd applied the finishing touches in the summer transfer window, and his masterpiece was complete and ready for all to see.
Two goals from Diego Costa sealed the deal early on but it was another player who caught the eye as the key cog in his machine; Matic.
The hulking Serbian has all the characteristics to be one of the great defensive midfield players. He gobbles up the ground in one gigantic stride, he tackles like a beast and runs like a monster. This was pre-season, and he was taking on all comers.
Having returned from Benfica in the January window, Chelsea fans only got a glimpse of what he was capable of last season - but this campaign should be his time to shine.
So it's disappointing to see Chelsea linked with a big-money move for Sami Khedira. The German is of course a fantastic player who would improve any squad, but he isn't the right man for the Blues.
Why? Well if there is one thing about Mourinho's best teams it's that they are usually fine-tuned machines with each player given a specific task to do for the greater good. Think about his monstrous first Chelsea side or the counter-attacking animal he crafted at Madrid. The sum is greater than its parts.
In Matic, Cesc Fabregas and Ramires (or even Marco van Ginkel) he has three players who complement each other perfectly; Matic is the muscle, Fabregas is the brains, and Ramires links the two together with his running and box-to-box play. Matic and Ramires may not be huge names like Khedira but they have the perfect blend of ability in the middle of the park to make Chelsea a force. Indeed, if their showing against Burnley is anything to go by, they are already just that.
It's not just that either - a glance at the stats will show you that Matic is unbelievably effective at his job. He won 30 more tackles than Khedira did in midfield last season, made 18 more interceptions and even played eight more key passes and got three more assist. He only played four more games than Khedira to achieve those numbers. His all-round game is hugely underrated.
Chelsea have a history if stock-piling players they don't necessarily need but that's a trend they need to buck with Khedira. It's time they gave a young player the chance to grow and demonstrate his undeniable talent.