Mallen's brace leads Dortmund to 4-0 win at Cologne

Donyell Mallen scored a brace as Borussia Dortmund claimed a 4-0 win at Cologne to officially kick off the second half of the Bundesliga on Saturday.

Third-placed VfB Stuttgart, meanwhile, were defeated 1-0 at VfL Bochum after the second half of the game only started following a massive delay.

Mallen got the opener in the 12th minute, finishing off a corner from Julian Brandt. Dortmund could have increased their lead still in the first half, but the second goal came only after the break when Niclas Füllkrug hit the net from the spot in the 58th.

Mallen then completed his brace in the 61st after he received a stunning and long cross-field pass from winter signing Ian Maatsen, and Youssoufa Moukoko added Dortmund's fourth in stoppage time.

Dortmund remained fifth in the table and sit outside of the qualification zone for the Champions League.

Stuttgart had the second half of their match at Bochum delayed in some 40 minutes because flags in the away block were blocking an emergency exit.

Stuttgart coach Sebastian Hoeneß and some of the players spoke to the fans to get them to remove the flags, but initially without success.

Matus Bero scored Bochum's winner shortly after the restart. Stuttgart tried to forced the equalizer, but were held by keeper Manuel Riemann and they can now slip out of the top three if RB Leipzig don't lose to leaders Bayer Leverkusen later.

Freiburg built a 2-0 lead against Hoffenheim thanks to Lucas Höler and Vincenzo Grifo. But things started looking bad once Wout Weghorst and Maximilian Beier equalized for the guests and Freiburg were down to 10 men after Manuel Gulde saw a red card in the 82nd.

But the hosts managed to score a late third goal with Roland Sallai to secure a 3-2 win.

Elsewhere, Eintracht Frankfurt gave up a 2-0 lead to concede a 2-2 draw to promoted Darmstadt and Heidenheim clinched a point in a 1-1 draw with VfL Wolfsburg.

There were again protests against the German Football League (DFL) decision to bring in an strategic partner and the match between Cologne and Dortmund was interrupted for some seven minutes after threw chocolate coins on the pitch.

The DFL aims to boost its business model and international marketing with the income from the strategic partner who is to have no saying in sporting matters such as fixtures lists. But fans have a strong position against this step.

Sunday's schedule include Bayern Munich v Werder Bremen and Borussia Mönchengladbach v Augsburg. The match between Mainz and Union Berlin, originally scheduled for Friday, was cancelled due to wintry weather conditions.