The best opening act you've ever seen & heard?

Return to Forever at the Capitol Center in '74 (I think). 

I saw The Feelies open for R.E.M. (Life's Rich Pageant tour) on 11/6/86 (had to look that one up on my partial list of concerts seen) at The Felt Forum (now The Hulu Theater at Madison Square Garden).  I'd never before and have never since seen an opener be so enthusiastically well received by a crowd. Sadly, during the first song of R.E.M.'s encore that night, the crowd rushed the stage and Michael Stipe pulled a girl up on stage from the front of the crowd (it was SRO as I recall, no seats) who was apparently getting crushed.  The rest of the band stopped playing a few seconds later.  They did one song after that if I remember correctly and then called it quits. Michael was quite upset.

I saw INXS open for the Go-Gos in the early 80s and OMD open for Depeche Mode for the Music for the Masses tour in May 1988. Incredible acts.

1. 25 November 1973. Mott the Hoople concert in Edinburgh. Their support act was a largely unknown bunch of theatrical, Lycra-clad rockers, who got boo’d by the audience of cool dudes when they came on. An hour-and-a-half later, Mott the Hoople got boo’d when they took over. The band? Queen 😁

2. 9 October 2011. Mark Knopfler opening for Bob Dylan at Braehead Arena, Glasgow. Knopfler was on superb form, which was just as well, as Dylan was rubbish - waited 30+ years to see the bugger, and we all walked out halfway through.

@drinaldo: I have a friend who saw the last show Jeff Beck played with The Yardbirds. It was Jeff and Jimmy Page on guitars, and Chris Dreja on bass. He saw them again the following night, and Jeff was gone. I never managed to see the band, damn it.