That result means victory in Italy is a must with only seven games remaining in the regular season, three of which are against sides currently above Munster in the table.
But with home games to come against Ospreys and Connacht in their next two fixtures, Penney believes leaving the Stadio di Monigo with victory will put Munster back on track for a tilt at the RaboDirect PRO12 title.
"It's a critical game this weekend, we don't want to get left behind the top four, we've got to be there or thereabouts over the next few weeks if we are going to be in contention," said the New Zealander.
"The travel is difficult but it's probably not as bad as last week where we were flying to Heathrow then jumping on the bus for four hours to Scarlets, but it's just part of the nature of the beast.
"It's great to finish this little run of away games and if we can do a great job over in Treviso then we head back here with a tough but critical game with Ospreys so if we can nip a couple of points off them we might be able to slip in front.
"Then we head in to the final block with Connacht and Glasgow before the Heineken Cup quarter in good shape looking for a top four spot and looking to fight it out for the silverware in the Rabo."
Full-back and centre Felix Jones and James Downey return to Munster's starting XV for Sunday's clash
Casey Laulala is another who returns to the starting XV for the first time since he partnered Downey in the PRO12 match against Ulster in Thomond Park Stadium just after Christmas.
And while Penney praised the spirit of some of his younger players he will be delighted to welcome back the trio.
"It was a really disappointing outcome at Scarlets but there were elements of it that were really good, we've got to take some positives and the form of some of the young blokes coming through was great," he added.
"That doesn't overshadow the outcome but there are some glimpses of hope there.
"Being tenacious is something the boys take pride in and fighting right until the end was good and while the defence was a bit leaky at times we've scrambled and worked hard and showed some character."
Meanwhile, Treviso are boosted by the return of flanker Marco Filippucci, who starts on the replacements bench after three months out injured.
But it will be a squad heavily weakened by their missing international contingent, with ten of Italy's starting XV for the game against Wales hailing from Treviso.
At Stadio Monigo, 3pm local time (2pm Ireland and UK)
Referee: Neil Paterson (SRU, 48th competition game)
Assistant Referees: Stefano Traversi, Stefano Marrama (both FIR)
Citing Commissioner: Achille Reali (FIR)
TMO: Mauro Dordolo (FIR)
Live on Sportitalia
Delayed coverage on TG4