Defeat for Leinster and victory for fourth-placed Ospreys at home to Zebre on Saturday night would make their challenge even tougher - and Richardt Strauss is determined to prevent that.
"It's massive for us to get back into (the top four) and to be in it at the end of the season," he told the club website. "For us this weekend it's just to go out and win the game."
Ospreys, meanwhile, have not lost a league match at the Liberty Stadium since February 2014 and won this season's corresponding fixture with Zebre - albeit by the narrowest of margins.
Ulster and Munster also have designs on securing a top-four finish and resume domestic action with home games against Cardiff Blues and Connacht respectively.
Second-placed Ulster find themselves four points behind Glasgow and four clear of Leinster as they bid to get over the line, but the Blues enjoyed victory over Connacht last time out and are the most prolific of the GUINNESS PRO12's bottom half with 35 tries.
Munster have traditionally held a hex over interprovincial rivals Connacht, having lost just one of their 24 league meetings before this season.
But their clash on New Year's Day saw Pat Lam's men reign supreme and the chance to complete a double makes their clash at Thomond Park on Saturday evening all the more intriguing.
Scarlets and Edinburgh are set to face off with the loser knowing that securing a top-six finish and European qualification will become increasingly difficult with only four rounds to go.
"We are under no illusions that we have to win this weekend," Scarlets boss Wayne Pivac told the Llanelli Star.
"If we can get across the line, hopefully we will have a bit of breathing space over Edinburgh and other teams can do us some favours."
And the round's action concludes when 11th-placed Benetton Treviso entertain Newport Gwent Dragons in tenth at Stadio Monigo.
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