A JEKYLL and Hyde performance saw Knights take a commanding 31-0 lead in a devastating start before allowing Titans back into the match in the second half.
But they finally managed to make the game safe to keep alive their hopes of reaching the semi-finals of the promotion play-offs.
Knights produced some superb rugby at the start with winger Matty Williams diving over in the opening minute.
They increased the lead when they were awarded a penalty try after pushing the Rotherham pack over their own line, and Matt Challinor bagged a third try after 21 minutes with Andy Wright claiming the fourth seven minutes later, with Tristan Roberts converting for a 24-0 lead.
Hooker Steve Lawrie celebrated his starting spot in the injury hit team with a try on 34 minutes, which Roberts converted, but the Titans fight back began when Sean Dougall pulled back a try just before the break.
Doncaster began to flounder after the interval and Rotherham cashed in when Louis McGowan touched down with Juan Pablo Socino converting, and fly half Socino then improved his own 48th minute try to close the gap to 31-19.
Steve McColl kicked a penalty for Doncaster on the hour mark, but Rotherham continued to closed the deficit with Ryan Burrows’ try being converted by Socino to leave them trailing by only eight points.
But time ran out for the Titans and Doncaster made sure of the win with Wright scoring a second try, which McColl converted.