Meanwhile, at the Liberty Stadium, in what would be one of the play-off pairings if the season was to finish now, the records again seem to favour the unbeaten team, as Connacht have not won on Ospreys soil since 2004.
Ulster are the third Irish team in action on Friday night when they also travel to Wales, to take on the Newport Gwent Dragons at a refurbished Rodney Parade.
Ulster lost their 100% winning record last time out and will be looking for a victory to keep themselves firmly established in the play-off zone.
The three remaining round 5 games all take place on Saturday, one each in Italy, Wales and Ireland. Italian confidence was boosted last round with both teams winning in the same round for the first time since joining the competition.
Benetton Treviso have the best chance of repeating that success as they welcome the Scarlets to Stadio di Monigo, the Welsh region being subjected to Treviso's first league win in the opening round last season.
Airoini, on the other hand, will need all the confidence last weekend's win over Edinburgh can give them as they have to face Heineken Cup holders Leinster on their own patch.
The round wraps up with Cardiff facing Glasgow Warriors at the Cardiff City Stadium. The Blues' won 2, lost 2 record sees them just outside the play-offs, while Glasgow are at the wrong end of the table for their liking, so a victory is required for each side - something has to give.
Friday, September 30 -
Newport Gwent Dragons v ULSTER, Rodney Parade, 7.05pm (live BBC 2 Northern Ireland/RTÉ Two/BBC 2 Wales)
Edinburgh v MUNSTER, Murrayfield, 7.30pm
Ospreys v CONNACHT, Liberty Stadium, 7.30pm
Saturday, October 1 -
Benetton Treviso v Scarlets, Stadio di Monigo, 3pm
LEINSTER v Aironi Rugby, the RDS, 6pm
Cardiff Blues v Glasgow Warriors, Cardiff City Stadium, 6.30pm (live S4C)