[plt-scheme] example of match quasipattern

I don't understand the match quasipattern. Could someone give an example of it's
use?

I am trying to do something like

(let ((sym 'duck))
    (match-lambda
      [(`, at sym . rest) rest] 
      [else #f]))

that would match (list 'duck) or (list 'duck ...). Currently it matches any
pair. I realize

(match-lambda
  [('duck . rest) rest]
  [else #f]))

would work. But how can I do it with a quasipattern?

Thanks,
David