Marco Borriello and Mirko Vucinic each converted second-half penalties as Roma won the Eternal City derby against Serie A leaders Lazio this afternoon.
Borriello scored after the referee ruled that Stephan Lichtsteiner had deflected Fabio Simplicio's goalbound shot with his hand.
Simplicio almost doubled the advantage when he hit the crossbar, only for Lazio's Pasquale Foggia to nearly equalise when his effort rebounded off the woodwork seven minutes from time.
Baptista then earned the second penalty after being brought down by Andre Dias inside the area.
The outcome was Lazio's first defeat since August 29 and saw their five-match winning streak come to an end.
Lazio's lead at the top of the standings has been cut to two points because AC Milan won 3-1 at Bari today. Roma, meanwhile, have climbed to seventh in the standings.
Lazio never tested Roma goalkeeper Julio Sergio in the opening half as the visitors - without suspended captain Francesco Totti - dominated possession and forced home goalkeeper Fernando Muslera to make his first save in the 20th minute.
At the other end, Hernanes' chested down Stefan Radu's cross but his volley went over the bar.
Midway through the first half, Daniele De Rossi served John Arne Riise and his 20-yard effort towards the centre of goal was met by a fine save from Muslera.
Muslera was again involved on the half-hour mark and had to parry away Simplicio's shot from outside the area.
Roma coach Claudio Ranieri was forced to make his first substitution in the 39th minute with Leandro Greco replacing an injured Jeremy Menez.
Greco then had a goal disallowed after Borriello was called for offside.
On the stroke of half-time, Hernanes tried his luck from long distance but his effort went high and wide.
Lazio coach Edy Reja brought in Mauro Zarate in place of Tommaso Rocchi after the restart.
The Biancoceleste first tested Julio Sergio in the 48th minute with the goalkeeper saving Cristian Ledesma's free-kick - but four minutes later Roma broke the deadlock.
Muslera got a touch on Borriello's strike towards the bottom right hand corner but it was not sufficient to stop the ball from going inside the net.
Lazio responded with Floccari's powerful header from Lichtsteiner's cross going just over the bar.
In the 65th minute, Lazio almost equalised but Julio Sergio made a great save to clear Hernanes' close-range volley.
With 13 minutes remaining, Roma were unlucky not to double their lead with Simplicio's strike rebounding off the bar.
Lazio had their best chance to equalise with Foggia's close-range effort finding the woodwork - and three minutes from time Vucinic 's spot-kick towards the far post beat Muslera.