Despite the defeat the previously unbeaten Ospreys, who registered a losing bonus point, still went to the top of the table.
Man of the match Jackson's six penalties stole the honours from opposite number Dan Biggar who had put the Ospreys in to a 12-0 lead with four penalties.
Newport Gwent Dragons maintained their perfect home start to the season by beating Zebre 30-7 at Rodney Parade.
Two tries by Wales Under-20s wing Hallam Amos and another from Lewis Evans secured the Dragons' third win of the campaign and condemned Zebre to yet another pointless evening.
Connacht slumped to their fourth defeat in five matches after going down 23-3 to fellow strugglers Benetton Treviso.
Alessandro Zanni and Luca Morisi crossed for second-half tries for Benetton to seal a second win of the season for the Italian side, with Connacht's only contribution to the scoreboard coming from Dan Parks' penalty after the interval.
The result leaves Connacht stuck in the bottom two of the standings on four points, the same as last-placed Edinburgh who are in action on Sunday.
- Sports & Recreation
- Newport Gwent Dragons
- Dan Biggar