The result left Roma third on 67 points from 34 games, three ahead of city rivals Lazio and four ahead of Inter Milan who both have a game in hand in the three-way battle for two Champions League slots.
With one eye on Tuesday’s clash with Liverpool at Anfield, Roma coach Eusebio di Francesco left the bulk of his regular starters on the bench and the makeshift side delivered with a classy performance at relegation-threatened SPAL.
After a cagey opening half-hour, Vicari fired Roma ahead in the 33rd minute when he poked the ball into his own net from seven metres in an attempt to divert a Lorenzo Pellegrini pass to the advancing Kevin Strootman.
SPAL keeper Alex Meret made two fine saves before halftime but was powerless in the 52nd minute, when Nainggolan unleashed a swerving volley into the bottom right corner from the edge of the penalty area.
Pellegrini provided another superb assist in the 59th for Schick to head home from close range as Roma turned on the heat, with Stephan El Shaarawy missing several chances including a diving header which hit the post.
Roma keeper Alison Becker was rarely called into action but made two good saves to deny Alberto Paloschi and Mirko Antenucci, leaving SPAL in 17th place on 29 points from 34 games, one ahead of Crotone who have a game in hand.
In the day’s other matches, Sassuolo are at home to Fiorentina (1600 GMT) while AC Milan take on bottom team Benevento in the evening kick-off (1845 GMT).
The round’s stand-out fixture is Sunday’s potential title showdown as champions and leaders Juventus (85 points) take on second-placed Napoli (81) at home.
(Writing by Zoran Milosavljevic; Editing by Clare Fallon)
