Olof Mellberg and Pavel Nedved added the third and fourth goals after injury-and-suspension ravaged Roma ran out of steam.
The win puts second-placed Juve four points behind leaders Inter Milan, who have 10 games remaining and host bottom side Reggina on Sunday.
"We must think about our results without looking too much at Inter," Iaquinta told Sky television.
"We have nine games left and we have to go on the field with the mentality to win all nine."
The match started scrappily but Iaquinta produced the first bit of class when he was given space just inside the area to fire into the corner of the net.
Loria, much derided by Roma fans after several error-strewn displays this term, was overjoyed to turn in the equaliser just after the break when Juve failed to defend a flat corner.
But Iaquinta, who hopes to be named on Sunday in Italy's squad for the World Cup qualifiers with Montenegro and Ireland, soon had Juve back in the lead.
Zdenek Grygera's cross deflected up off John Arne Riise and former Udinese striker Iaquinta jumped highest to head home.
Riise then cleared Alessandro Del Piero's shot off the line but Juve were not to be denied and Mellberg powerfully headed in a corner before substitute Nedved matched last weekend's scoreline against Bologna with a fierce shot from distance.
Roma, without the injured Francesco Totti and suspended Daniele De Rossi, are two points behind fourth-placed Genoa in the race for the final Champions League qualifying spot.
Genoa host Udinese on Sunday before third-placed AC Milan travel to Napoli.
Eighth-placed Lazio's hopes of European qualification took another blow in the early kickoff when Delio Rossi's side lost 1-0 at Catania.
Striker Michele Paolucci tapped in midway through the first half following a swift counter attack to all but end any lingering fears of relegation for the Sicilians.
Lazio, beaten 3-0 at home by struggling Chievo last weekend, should have equalised but Albano Bizzarri saved Goran Pandev's second-half penalty after the Macedonian had been fouled.
