Werder Bremen coach Viktor Skripnik has admitted he will need to consider a change in system in order to stop free-scoring Borussia Dortmund in the Bundesliga on Saturday.
Thomas Tuchel's Dortmund have won four straight games in all competitions, scoring 17 goals in the process.
In-form striker Pierre-Emerick Aubameyang, scorer of 20 goals in 17 appearances this season, netted hat-tricks in the 3-1 Europa League win at Qabala and the 5-1 Bundesliga hammering of Augsburg last week.
Those results were followed up with a 7-1 demolition of Paderborn in the DFB-Pokal on Tuesday, in which Gonzalo Castro scored twice, while Marco Reus has three goals in the last four matches.
Second-placed Dortmund, who trail leaders Bayern Munich by seven points, will be heavy favourites to maintain their run of form with victory at the Weserstadion.
But Bremen go into this contest on the back of consecutive wins having previously struggled for form at start the campaign.
Anthony Ujah was on target twice in a 3-1 league success at Tuchel's former club Mainz last week, and the Nigeria international scored the decisive goal in Wednesday's 1-0 Pokal triumph over Cologne.
Despite the recent upturn in fortunes Bremen are still a 14th in the Bundesliga having taken 10 points from as many games.
And, looking ahead to the daunting visit of Dortmund, Skripnik told the club's official website: "Saturday will certainly not be easier. We have to be equally focused.
"The 4-1-4-1 system is working very well for us at the moment. We have deserved the last two wins, but you can never rely on one system, and we will have to think of an alternative."
However, midfielder Fin Bartels is more upbeat over Bremen's hopes of a positive result, saying: "Dortmund are riding on a bit of a wave, and are very dangerous going forward.
"It will be a difficult game, but we are very solid at the back at the moment. This will certainly be helpful against Dortmund."
