Shamrock Rovers moved to within four points of SSE Airtricity Premier leaders Dundalk on Tuesday night.
Mikie Drennan scored his tenth of the season, but was later sent off as Pat Fenlon's side thrashed Derry City 4-1 in Tallaght.
Derry's Ryan McBride was also shown a straight red card after just 13 minutes.
Further goals from Gary McCabe, Kieran 'Marty' Waters and Brandon Miele during the second-half sealed a comfortable win for Rovers before substitute Ryan Curran grabbed a late consolation for the Candystripes.
The red cards mean, McBride will miss Friday's game away to Drogheda United while Drennan will be suspended for the Dublin derby with Bohemians.
The defeat was Derry's eighth in the league and Peter Hutton's side remain 9th in the table, 2pts above the bottom three.