Nearly 30 years after being banned from Saturday Night Live, the Replacements kept things lean and mean on NBC last night. Appearing on The Tonight Show Starring Jimmy Fallon, the Minneapolis cult heroes tore through a robust performance of their 1987 song “Alex Chilton,” keeping their sound clean and crisp throughout like they’d never left at all. Lead singer Paul Westerberg told the crowd at Sunday night’s Boston Calling Festival that when the band had initially been booked to play The Tonight Show, producers shot down some song ideas, including an free-for-all segment. “They didn’t want me improvising,” Stinson said with a sneer, but if “Chilton” was their reigned-in performance, we think they did just fine. Watch the band’s triumphant return to NBC above.