In the second half of the season, with the exception of Dybala when fit, Matic has been Roma's best player whenever I've watched them. Not sure how he was in the 1st half, but he's been very good in the second half of the season, especially their European games.I didn't watch too many games of Roma this season, but everytime when Matic was on pitch, he was more than decent, including the match against us.
Smalling is also ok for them. The problem are his two colleagues.
Agree on Smalling as well who is easily their best defender. Ibanez makes mistakes every game and Mancini is a loose cannon who looks on the verge of being red-carded every time I watch him.