"We are taking the European Challenge Cup very seriously," said Horstmann. "It was tremendously frustrating to lose in the final back in May and we want to have another shot at the title and win the trophy.
"And there is a bit of wanting to win some silverware while also qualifying for the 2009 Heineken Cup as we aim for another final.
"Playing in the Heineken Cup is the next stage for us to target - and there is that carrot there for the European Challenge Cup winners - while it is a long time since the club picked up any silverware."
Horstmann admits Warriors have been handed an interesting pool draw this season.
"We have a varied mix in our Pool of an Italian, a Romanian and a French side and that should make all our matches interesting experiences," he added.
"What we are after is a similar solid and winning start to the group stages as last season as that ultimately earned us home ties in the quarter-finals and semi-finals, which is so important once you are in the knock-out stages.
"The players do not know a great deal about Petrarca - which means we are going a bit into the unknown - but our analysis team will have done their homework and will fill the players in on what they can expect."
Worcester beat London Irish 22-5 in Round 1 of the EDF Energy Cup last weekend and are keen to maintain the winning momentum.
"That was a really good win for us," said Horstmann. "It was frustrating to lose to Harlequins last week and while there was a quick turn-around for the London Irish game the players stepped up and got a great result.
"We now have two European weekends followed by the last two rounds of the EDF group stage so it is vital we build on this and get some consistency going in our game.
"But we won't be underestimating anyone. We are up against Bucuresti Oaks again and last season they beat Montauban and GRAN Parma in our Pool so we are well aware of what they are capable of achieving.
"It was tough playing the away game against Bucuresti last season as we had difficult and very cold conditions after a long trip but this time those matches are coming earlier in the tournament which should make it a bit easier.
"These European Challenge Cup matches are coming at a good time for us and we know we have to make that strong start if we want to go all the way to the final again."