It takes a singer with a pretty huge voice to cover a duet by themselves.
Carly Rae Jepson is that singer. This song, originally sung by Fleetwood Mac and performed at a festival in tribute of the band, was such a duet. Clearly, she's making some concessions with the chorus, but she makes it work.
Unfortunately, it seems like this was a one-time performance, which is a shame, because she absolutely slayed this song.