Premier Division leaders Dundalk left the Brandywell with the full set of points on Friday night thanks to a 2-0 win over Derry City.
Derry's task of pulling of a shock win against the title favourites was made even tougher when Conor McCormick was sent off on 23 minutes.
The incident infuriated the Derry bench which resulted in assistant manager Paul Hegarty also being sent off for arguing with officials.
By the break Dundalk were 1-0 up thanks to a goal from Ciaran Kilduff three minutes into injury time.
For long periods of the game Derry were a match for Stephen Kenny's side who sealed the victory with two minutes on clock as David McMillian scored their second.
Second bottom Sligo Rovers closed the gap to Derry to three points with a 4-0 win at Drogheda United.
Derry and Sligo will face off on Monday night at the Showgrounds with crucial points up for grabs.
Elsewhere Cork lost to Limerick 3-2 which means Dundalk have moved seven points clear at the top.
Bohemians won 3-nil against Galway, St. Pat's notched the only goal in their match with Bray Wanderers and Longford Town lost 3-1 at home to Shamrock Rovers.