Derry suffered their first Airtricity Premier Division defeat of the campaign after losing to Shelbourne in Dublin.
Both sides went close before Philip Hughes fired home for Shels two minutes before the break after a mistake from defender Stewart Greacen.
The hosts cleared off the line from a Patrick McEleney free-kick and Barry Molloy hit the Shels crossbar.
City striker Rory Patterson missed an easy chance before being sent-off for two yellow cards in injury-time.
Paddy Kavanagh squandered an early opportunity for Shelbourne while Candystripes forward David McDaid had a shot saved by Sean Delaney.
It was a powerful strike from Hughes which keeper Gerard Doherty could only help into the net.
Derry came closest when Molloy saw his curling shot kept out by the woodwork after 71 minutes.
Patterson should have converted from Stephen McLaughlin's cross with seven minutes left and the former Linfield player was dismissed in the third minute of added time.
Friday 16 March
Airtricity Premier Division results
Cork City 1-1 Shamrock Rovers
Drogheda Utd 0-0 Dundalk
St Patrick's Athletic 1-1 Monaghan Utd
Sligo Rovers 1-0 Bohemians
UCD 2-3 Bray Wanderers