Rush's 'Limelight' meets Thin Lizzy's 'Jailbreak' in round two of Ultimate Classic Rock's March Riff Madness.

Last week, we cut down the initial field of 32 of rock’s most iconic riffs down to 16. And this week we’ll halve it again, then repeat the process for the rest of the month until we theoretically arrive at the most awesome riff in all of rock history.

Rush's 'Limelight' fought off a tough round one challenge from 'American Woman' by fellow Canadians the Guess Who. But they'll get strong competition from Thin Lizzy, whose 'Jailbreak' pulled off a stunning upset by knocking out one of rock's defining riffs, the Rolling Stones' '(I Can’t Get No) Satisfaction.’

Which riff will make it to the quarterfinals? It's your call. Everyone can vote once per hour until round two of March Riff Madness closes on Sunday, March 16 at 11:59PM ET. The ultimate March Riff Madness winner will be revealed on Tuesday, April 7.

Watch Rush Perform 'Limelight'

Watch Thin Lizzy Perform 'Jailbreak'