Jackson scored 21 points to add to his 50 so far in the tournament
Saracens booked their place in the quarter-finals of the European Challenge Cup with a 36-19 win over Italian side Viadana.
Sarries took an early lead from a Glen Jackson penalty, but Viadana hit back before the home side took control.
Noah Cato, Kameli Ratuvou and Adam Powell ran in tries, all converted by Jackson, who added four more penalties.
They qualify along with London Irish and Worcester who secured comfortable victories on Saturday.
Peter Hewat helped himself to five tries as the Exiles crushed Connacht 75-5 at the Madjeski Stadium.
Topsy Ojo also bagged a pair as six different players shared 11 tries.
Worcester booked their last-eight spot with a 38-19 win over Bucuresti.
Northampton reached the quarter-finals by defeating Montpellier 28-24 in France on Thursday, while Bristol won 37-19 at Toulon on Friday.
Andy Goode capped his England call-up by converting Norman Ligairi's late try as Brive won 10-9 at Newcastle.
Newcastle had taken a 9-0 lead through three Tom May penalties but now find themselves third in Pool Four.
They must now win their final pool game in Spain against Cetransa El Salvador, to try to qualify as a best runner-up.