Paris - Ulster, the 2012 runners-up, reached the Heineken (European) Cup quarter-finals for a third successive season on Friday with a 23-6 win over Glasgow at their rain-lashed Ravenhill home in Belfast.
Ulster's place in the last eight was guaranteed when Pool 4 rivals Castres were beaten 18-12 by Northampton.
The Irish side were in charge in the first-half against a Glasgow side who had lost all of their four group games.
South African scrumhalf Ruan Pienaar gave them the lead with an early penalty before giant Kiwi No 8 Nick Williams barrelled over for his first try of the tournament but seventh of the season just before the 20-minute mark.
Pienaar popped over the conversion for a 10-0 half-time lead with the Scots having seen Duncan Weir miss two kicks at goal.
But Weir reduced the deficit early in the second half with his first successful penalty and then added a second, making the most of Ulster being reduced to 14 men when lock Iain Henderson was yellow-carded for not rolling away.
Pienaar calmed Ulster nerves with a penalty after 62 minutes to give his team some breathing space at 13-6 but then went wide with another attempt soon after.
Late tries from Kiwi fullback Jared Payne and centre Darren Cave eventually gave Ulster a comfortable looking victory and helped erase memories their 10-9 loss to Northampton just before Christmas.
Elsewhere on Friday, Montpellier scored four-tries in a 27-6 bonus-point win at Sale to keep alive their hopes of qualifying from Pool 6.
Heineken Cup results on Friday:
Northampton 18 Castres 12
Ulster 23 Glasgow 6
Sale 27 Montpellier 6
Racing Metro v Saracens
Harlequins v Connacht
Zebre v Biarritz
Clermont v Exeter
Leinster v Scarlets
Toulon v Cardiff Blues
Edinburgh v Munster
Ospreys v Leicester
Toulouse v Treviso
European Challenge results on Friday:
Bordeaux-Begles (FRA) 26 Gloucester (ENG) 31
Played on Thursday:
Mont de Marsan (FRA) 14 London Irish (ENG) 20
Bayonne (FRA) 25 Newport-Gwent Dragons (WAL) 22
Rovigo (ITA) v Worcester (ENG)
Bizkaia Gernika (ESP) v Perpignan (FRA)
London Wasps (ENG) v Mogliano (ITA)
Bath (ENG) v Agen (FRA)
Calvisano (ESP) v Bucharest (ROM)
London Welsh (ENG) v Cavalieri Prato (ITA)
Grenoble (FRA) v Stade Francais (FRA)