Köln made light work of an out-of-sorts Union Berlin with a dominant 5-0 display to reach the DFB-Pokal's last-16.

On a rainy night at the Rhine-Energie Stadion, a Said El Mala and Linton Maina inspired 1.FC Köln to advance past a defensively shaky 1.FC Union Berlin with ease. René Wagner's typically goal-shy side ran riot, elimination their visitors from the cup on a 5-0 scoreline.

Union Berlin seemed to settle into this knockout tie slightly better as Tim Skarke put Marvin Schwäbe to work with an early save. Köln would respond at the other end with Linton Maina and Marius Bülter threatening from some of Union Berlin's defensive lapses.

After Said El Mala's work, Maina appeared to spurn the best opportunity of the half when the his shot cannoned off the upright. But the duo linked up in reverse order to get the lead. Maina slipped El Mala in on the left, enabling him to open his body and place it in the far corner. 

The visitors from Köpenick simply couldn't live with Köln's deadly wingers after the break. A loose pass picked off by El Mala left the 20-year-old with the simple task of feeding Maina with a whipped pass which required a deft touch to steer beyond a hapless Raab.

Mauro Lustrinelli's team, all at sea defensively, shipped a third before the hour. El Mala spotted the mismatch up against Zeno van den Bosch, turning him inside out before bending his shot from a narrow angle. Köln in dreamland. Union reeling in the Cathedral City.

Further gloss was added to the scoreboard by substitute Isak Johannesson who tapped in a fourth. A five-star performance and a place in the last-16 was assured when Reigan Heskey set up Sebastian Seboulonsen who placed his shot inside the left upright emphatically.