Saracens fly-half Andy Goode was the real difference between the two sides, his 100 percent kicking record contributing 20 of their 25 points.
The visitors, who had second rower Kris Chesney sin-binned shortly before the half-time break, held a narrow 9-6 lead after the first 40 minutes, three Goode penalties doing more damage than two Phil Jones three-pointers.
After early penalties from Goode and Jones in the second stanza, the latter struck a huge penalty goal to tie the scores at 12-12 after 55 minutes, but the visitors' class began to shine through as they managed to keep their noses in front before going for the kill.
The kill came just a few minutes after Jones had tied the scores – with a Goode penalty in between actually taking the score to 15-12 – before skipper and star second rower Simon Raiwalui crashed over, Goode converting to make it 22-12 with more than 20 minutes remaining.
Raiwalui's try, which saw former All Black skipper Taine Randell up in support, was initiated by a wonderful run from Goode, the No.10 showing all the tricks in the book before slotting his sixth and final penalty in the 67th minute to leave the score at 25-12.
Saracens moved above Leicester on the Zurich Premiership table with this win, their third of the season, while Rotherham remain winless and without a single point after eight fixtures in the top-flight.
For Rotherham:Pens: Jones 4
For Saracens:Try: RaiwaluiCon: GoodePens: Goode 6