For all of the change and expensive outlay at Chelsea this summer, retaining the Belgian forward has been the most important business.
Alvaro Morata Chelsea's best bit of business? No, keeping crown jewel Eden Hazard is
Chelsea fans must be wondering what all the fuss was about. After reports manager Antonio Conte was unhappy with the club's ambivalence towards strengthening a squad that romped to the Premier League title seven points clear of their closest pursuers, the club will begin their title defence against Burnley on August 12 with a spine significantly strengthened by fresh blood.
Antonio Rudiger, Tiemoue Bakayoko and Alvaro Morata, signed from Roma, Monaco and Real Madrid respectively, each came for a pretty penny but add youth, hunger and, in the case of the latter two, a fair few winner's medals already hanging around their necks. The fact Conte also signed improved terms on his existing deal also laid to rest any simmering disquiet over the Italian's future.
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But perhaps the most significant piece of business the West London club has done over the summer is not in investment in uncut diamonds - Rudiger, Bakayoko and Morata have been acquired at an initial cost well over £130 million (Dh620m) - but in retaining their crown jewel.
Eden Hazard was back to his devastating best in 2016/17 after going off the boil following Chelsea's title success in 2014/15. A combination of injuries and a now infamous fallout with Jose Mourinho were consigned to history as the Belgian winger used his wizardry to leave defenders dumbfounded, never more expertly displayed than the solo goal against Arsenal in a 3-1 win at Stamford Bridge in February.
While the record books will show Diego Costa contributed 20 goals to Chelsea's title-winning campaign, the Spanish striker's disposition - never the sunniest even at the best of times - darkened significantly from January to May after a falling out with his manager after a lucrative move to China was quashed.
And this is where Hazard picked up the reins. If Costa is the brawn, Hazard is most definitely the brains. His cunning and guile set the tone for Chelsea in the second half of the campaign as they managed to keep their noses in front of Tottenham Hotspur down the home stretch.
His 16 goals in 36 appearances garnered admiring glances from Real Madrid, who are long-time admirers, with the former Lille player confessing last month that he would "consider" an offer should the Spanish champions firm up their reported €100m (Dh429m) offer.
A concern, other than one of the world's wealthiest clubs fluttering their eyelashes at one of your best players, is that in his five seasons at Stamford Bridge Hazard has yet to lead Chelsea to back-to-back titles. With Costa almost certain to depart before the transfer window closes this month, Conte must keep his Belgian magician - currently recovering from a fractured ankle - if he is to emulate his success at Juventus with successive championships.