After her triumph in Saturday's solo technical event, Romashina joined up with Kolesnichenko to wow the spectators in the Palau Sant Jordi with an energetic two-minute routine that earned the favourites 97.300 points.
Chinese twins Jiang Tingting and Jiang Wenwen were second with 94.900 points, while Ona Carbonell and Margalida Crespi delighted the home support by taking bronze for Spain with 93.800 points.
"I'm very happy to partner with her, we never had any conflicts," Romashina, a three-times Olympic champion, said of her new team mate Kolesnichenko.
"We felt comfortable from the very first day we started training together."
The Jiang twins, who won their first world championship medals in Rome in 2009, told reporters they would be retiring after the Barcelona championships.
(Writing by Iain Rogers in Madrid; Editing by Sonia Oxley)
