After edging this British & Irish Cup opener, it means they have still not lost against their South Yorkshire neighbours at home since 2011.
Rotherham had lost four of their six league games so far this season so this proved a welcome relief, head coach Justin Burnell making a raft of changes and including four players from Premiership club Gloucester.
Evans was the pick, the 20-year-old kicking five penalties and adding two conversions, including improving his smart try in the final play of the game.
Rotherham were unlucky to be only 18-10 at the break having dominated large parts of the first period against opponents who had lost just twice previously this term.
However, when another line-out went awry - it was a recurring theme for both sides - Latu Makaafi snaffled it and the ball was moved swiftly to the left where George Catchpole, the young centre on dual-registration from Leicester Tigers, squeezed over with just seconds of the half remaining.
Dougie Flockhart converted, adding to his 10th minute penalty, and so Doncaster were relatively pleased.
However, their discipline waned badly in the second period, as did their control, and Rotherham pushed on for a deserved win.
They had opened the scoring with Evans’ early penalty and, after Flockhart levelled, took the lead with the fly-half’s second kick.
His forwards then worked a good position for lock Toby Salmon to cross in the 25th minute, latching onto Gloucester prop Josh McNulty’s offload near the posts for Evans to convert.
When Doncaster hooker Ben Hunter saw another line-out go long in his own 22, Jarrad Williams managed to retrieve the loose ball only to lose it again, gifting Rotherham the chance to quickly attack, winger Jake Henry scoring his first try for the club in the 35th minute.
Evans added another penalty in the 48th minute but the visitors instantly replied when, after Doncaster’s pack drove close, their backs moved the ball for Lloyd Hayes - on his first return to Clifton Lane after leaving in the summer - to dummy his way over.
Flockhart’s kick made it 21-17 but there was no comeback from Clive Griffiths’ side.
Although Evans missed a relatively simple penalty, he did slot one 12 minutes from time to stretch Rotherham further in front.
When Knights hooker Ben Hunter was yellow-carded for a professional foul in front of the posts, Evans made sure at 27-17 and dummied over for his try at the death, too.
Rotherham Titans: Foley C; Foley B, Hudson, Barker, Henry; Evans, Walsh (Tressider 54); Williams T, Cole (Maddison 69), McNulty (Rees 62), Salmon (Tyas 46), Curry, Batley, Grange, Clarke.
Doncaster Knights: Jarvis (White 40); Flockhart, Catchpole, Hayes, Bulumakau; Humberstone, Edgerley; Hislop (List 65), Hunter, Sprotson (Quigley 40), Williams J, Nolan, Makaafi (Gray 70), Owen (Robinson 70), Shaw.
Referee: Jack Makepeace (RFU)