Castaignède, overlooked for selection in the French squad at the recent Rugby World Cup in Australia, has battled with injury in recent weeks, but he looked sharp on his return, running in two tries, converting three of his side's four scores, and adding a penalty for good measure.
Castaignède got the match off to the best start possible, rustling up the first try of the day after just one minute, with his protege, Colomiers' Denis Cech, running in a try just three minutes later. Castaignède missed the conversion of his try, but was successful with Cech's try, as Sarries found themselves in a healthy 12-0 lead.
The Castaignède show was not over, however, as he ran in his second try in the 21st minute, also adding the conversion this time for a 19-0 lead.
Despite being out of the game up till then, Rotherham, to their credit, did manage a try from No.8 Geraint Lewis in the 28th minute, with fullback Jon Benson slotting the conversion, narrowing the scoreline to 19-7.
That – 19-7 – was to be the half-time scoreline, with both kickers trading early second-half penalties to move the score along to 22-10 before England star Richard Hill secured the four-try bonus point by getting his side's fourth try in the 54th minute.
Castaignède added the conversion to give him a points-haul of 19 in his comeback game, while his side moved 18 points clear of Rotherham – who are yet to score a single league point in the 2003/04 season – at the bottom of the Zurich Premiership table.
For Saracens:Tries Castaignède 2, Cech, HillCons: Castaignède 3Pen: Castaignède
For Rotherham:Try: LewisCon: BensonPen: Benson