I'm certain if you break down the stats you will find that during the losing streak there was less scoring by most individual players and the goaltending was worse. That's why there was a losing streak!
As many have already pointed out, when your best players like Kovalev are producing, the team wins. Hence the losing streak is over.
This is about as direct a correlation you will get. Key players score more, team wins, they score less, team loses.