Chelsea opened Premier League play last weekend, and I could not have been the only viewer puzzled by the presence of a grizzled old … bum? … sitting among the Blues’ coaches.

It looked like the guy had not shaved in a while, and he had the sort of buzz haircut he might have done himself.

He was wearing what looked like the cheapest Chelsea shirt a fan could buy in the team shop, and his ample belly made the replica jersey hang over thin air, somewhere in the neighborhood of what looked like sweat pants.

He was a mess. But he was not a pitch invader.

He was Maurizio Sarri, Chelsea’s new Italian coach.

Sarri is known for several things, and some of them are positive.

On the negative side of the ledger … he is a heavy smoker who is desperate to light up during a match. He did so on the sidelines at some of his various stops as coach in lower-division Italian soccer. But he will have to abstain, during Chelsea matches, having been reminded by Chelsea owner Roman Abramovich that smoking is banned at the club’s Stamford Bridge grounds.

And there is his apparel, which makes Sarri probably the worst dresser among the Premier League’s 20 coaches. And the worst-dressed Italian coach, we feel safe to say, in the annals of the Premier League.

One British daily insisted Chelsea’s owner has ordered Sarri to ditch the T-shirt and sweatpants and wear a suit at matches. If that is so, Sarri is defying the boss, because in Chelsea’s two victories the coach has looked as slovenly as ever. As if he might have slept the previous night under a trestle.

Also, Sarri has been known to lose his temper. In January of 2016, when Sarri was the coach of the Italian side Napoli, be verbally abused Inter coach Roberto Mancini so emphatically that Sarri was suspended for two matches. Mancini suggested Sarri’s outburst was part of a pattern of behavior.

Then there are the upsides, including what appears to be Sarri’s tactical expertise and a preference for hard-charging, attacking soccer — which would appeal to Abramovich.

A year ago, in his second season leading Napoli, Sarri led the club to a second-place Seria A finish, having pushed serial Italian champion Juventus throughout the season.

That brought him to the attention of Chelsea, which which had parted ways with its previous Italian coach, the personally stylish but professionally dour Antonio Conte, who had lost the locker room last season after leading the club to the 2017 Premier League championship.

So, Chelsea’s coach is still an Italian, but instead of Conte and his leading-man looks (and suit and tie on the touchline), the London club has Sarri, who seems to understand how to score at will … but brings to Stamford Bridge a foul mouth and the fashion sense of a hobo.

Let’s just guess and suggest Sarri can wear whatever he wants as long as Chelsea is winning. A few losses, however, and the former banker will have to start dressing like one.