The New York mayor spoke out just as Buttigieg sounded the alarm in a post-caucus speech in the Silver State about Sanders’s momentum following his strong showings in the first three nominating contests.

“And hey @PeteButtigieg, try to not be so smug when you just got your ass kicked. You know how we form a winning coalition to beat Trump? With a true multi-racial coalition of working Americans: something @BernieSanders has proven he can do + you haven’t. Dude, show some humility,” de Blasio tweeted of the former South Bend, Ind., mayor.