First he pouched Elissalde's cute kick from a penalty to open his account before bursting clear from the halfway line and brushing off three men toscore the most popular try of the night.
Connacht exploited their man advantage with Daniel Riordan racing cleartoscore after a John Muldoon kick had deflected off Ulster's Mark Bartholomeusz.
Paul Hanlon's late equaliser for Hibernian made Dundee United pay for Swanson's ordering off after United had taken the lead after only two minutes when David Goodwillie broke cleartoscore.