Shamrock Rovers' winning start to the Premier Division came to an abrupt end as St Patrick's Athletic took the spoils in the Dublin derby at Tallaght.
After dominating much of the first-half, Rovers fell behind on the stroke of half-time as Billy Dennehy found himself free at the back post from a Graham Kelly corner-kick.
The start of the second-half began with the Rovers fans lighting flares but it was Liam Buckley's men that shone brightest in the opening stages of the second-half.
A Mark Timlin cross was met by a wonderful Christy Fagan header to double the away team's lead. Fagan's header was his fourth in four games and the fifth headed goal in a row for the Saints.
Having not conceded before this game, the Hoops now found themselves two goals down from the only shots on target they had faced.
Pat Fenlon's men tried to force their way back into the match and very nearly did.
It looked like referee Thomas Connolly had awarded the hosts a penalty when right-back Simon Madden went down in the box after a tackle from Ian Bermingham but, after pressure from the Pat's players to consult the linesman, the referee reversed his decision and awarded the Saints a goal kick.
Brendan Clarke in the Pat's goal was rarely tested and dealt comfortably with shots from Brandon Miele, Gary Shaw and Danny North.
Substitute Darren Clarke went close from a Rovers corner but failed to alter his feet fast enough to produce enough power on his header.
Shaw came closest to pulling a goal back close to the end but the Pat's defence managed to scramble the ball clear.
Pat's can put their title credentials to the test again next week when they face Dundalk as Shamrock Rovers game with Cork City has been postponed due to international call-ups.