A rocket shot from Francesco Totti gave holders Roma a 1-0 home win over Catania in their Italian Cup semi-final first leg yesterday.
In the other first leg, Serie A leaders Inter drew 0-0 at home to Lazio in a dire game on a slippery surface.
Lazio played their best side after resting some big guns in Sunday's 1-1 draw with Siena while Inter had a largely second string line-up, with David Suazo and Hernan Crespo their only available strikers due to injury and suspension.
The pair combined for the clearest chance when Crespo's effort was well saved before Inter defender Nicolas Burdisso hit the bar.
Visitors Lazio were generally better and were only foiled by some last ditch defending and the offside flag.
In Rome, Totti blasted in from 30 metres following Mancini's run and pass in the 47th minute to give his side the edge.
With the Serie A title race taking priority, Roma coach Luciano Spalletti also picked several reserves but they still dominated and will be frustrated not to have taken a bigger lead into the second leg in Sicily on May 7.
Totti, Ludovic Giuly and Cicinho went close to increasing the advantage while league strugglers Catania barely threatened in Walter Zenga's third game in charge.
"It will be a very tough match in the second leg and we still need to earn our qualification," Spalletti told reporters.
Roma, who have met Inter in the last three finals, are four behind their rivals at the top of Serie A.
The Coppa Italia final takes place in Rome on May 24.
Juve beat Parma 3-0
Juventus all but booked a place in next season's Champions League qualifiers thanks to a 3-0 win over Serie A strugglers Parma last night.
David Trezeguet appeared offside when he tapped the ball in on 16 minutes after Mauro Camoranesi's header hit the post.
Winger Raffaele Palladino made sure Juve took full advantage of their game in hand when he buried the second on the half hour and Stefano Morrone's own goal made it three before Parma defender Fernando Couto was sent off for protesting.
Third-placed Juve have 64 points, 12 ahead of Milan in fifth with five matches to play. Claudio Ranieri's side are seven behind second-placed Roma.
Hector Cuper's Parma, who were saved from relegation last season by then-coach Ranieri, are one point and one place above the drop zone.
The original game was postponed last month when a Parma fan was knocked down and killed by a Juve fans' coach on the way to the match.
Next fixtures
Saturday: 18.00 Roma vs Livorno. 20.30 Fiorentina vs Palermo.
Sunday: 15.00 Atalanta vs Juve; Cagliari vs Empoli; Catania vs Lazio; Milan vs Reggina; Parma vs Napoli; Sampdoria vs Udinese; Siena vs Genoa. 20.30 Torino vs Inter.