Shankar, an Indian all-rounder, soon brought up his half-century in 24 balls with a six-hitting blitz from his South African teammate in an unbeaten 87.
Gujarat, for whom winning the Indian Premier League title last year was a fairy tale, moved to the top of the 10-team table with six wins from eight matches.
Two-time champions Kolkata, led by Nitish Rana, are in seventh place with six defeats in nine matches.