1. FC Union Berlin booked their place in the last 16 of the DFB Pokal with a 3-1 win after 120 minutes at SV Waldhof Mannheim.

Taiwo Awoniyi came off the bench towards the end of the 90 and fired the game-changing second goal early into extra-time at the Carl-Benz-Stadion. Kevin Behrens then made the tie safe with his second of the night with two minutes to go in the additional 30.

But Mannheim had started the Round 2 match with their tails up as Alexander Rossipal scored in the fourth minute. Despite the rip-roaring start of the third division outfit, Union bounced back and Behrens equalised after 18 minutes.

Waldhof Mannheim: Bartels; Sommer, Seegert (Gohlke 91), Rossipal, Odonkor; Russo, Höger, Costly; Lebeau (Ünlücifi 101), Schnatterer, Jurcher (Martinovic 61)

1. FC Union Berlin: Rönnow; Knoche, Baumgartl, Jaeckel; Trimmel (Wszolek 102), Oczipka (Gießelmann 90), Prömel, Haraguchi (Teuchert 71); Becker (Awoniyi 71), Behrens, Voglsammer (Khedira 57)

The Köpenick club suffered a bitter late shock in Stuttgart to leave with one point instead of three on Sunday. Three days have passed and Union set up with four changes from the weekend – out went Andreas Luthe, Niko Gießelmann, Rani Khedira and Taiwo Awoniyi; in came Frederik Rönnow, Bastian Oczipka, Kevin Behrens and Andreas Voglsammer. Having knocked out Eintracht Frankfurt in Round 1, Union needed no further warning signs from third-division opposition. Patrick Glöckner's side started at a furious speed at the Carl-Benz-Stadion, with around 14,000 home supporters in attendance. Marc Schnatterer's thumping cross into the box couldn't be scrambled clear by the red shirts and defender Rossipal made no mistake to score after just four minutes. The home crowd pushed their team on and Urs Fischer's side had to get a grip of things as quickly as possible. Marcel Costly and Schnatterer combined in and around the box on 10 minutes but the former Heidenheim midfielder was not supported by his team-mates. As the Bundesliga side started to settle in possession, Urs Fischer's team were able to level on 18 minutes. Sheraldo Becker did well to make something out of nothing on the right-hand side, getting the ball into Mannheim's box. Voglsammer won the knock down at the opposite side of the 18-yard-area and Behrens finished off superbly to score in the third different competition this campaign for Union. The equaliser helped the visitors get further up the pitch and play the game we've come to recognise from Union. But the away side were never out of danger for the first 30 mins and number one Rönnow made his first significant save from Rossipal. The last quarter of an hour of the first 45 was better from Union Berlin. The likes of Grischa Prömel and Genki Haraguchi commanded more time and space, while Becker continued to be a threat in one-v-one battles with left-back Anton Odonkor. It was the Dutch winger who created Union's second good opportunity of the game, driving in from the right and putting Jan Bartels' box under pressure. Voglsammer came in from the left to attack the ball but Marcel Seegert did enough to clear and protect his side's goal.

After time to take a breath in Mannheim, the home side returned with the same energy as the first half. Odonkor fired over from about 15 yards out on 47 minutes before Gillian Jurcher threatened with his space in behind the Union backline. Mannheim were on top at the start of the half but weren't able to put Rönnow under serious pressure. Jurcher took a pass in on 53 minutes and looked to chip over the Danish goalkeeper but it went wide of the target. Fischer went quickly to his bench on 57 minutes to add some stability in midfield with Rani Khedira taking Voglsammer's place. A chance came to Becker on the hour mark, the winger dribbling in from the left but skewing the shot wide of the target. Both teams gave as good as they could going forward despite the players starting to run out of gas due to the frantic intensity. Lebeau shot from range off Knoche but Benjamin Brand waved away handball claims. The referee similarly at the other end ignored shouts for a handball against Rossipal and a penalty for a challenge on Prömel. Fischer went for a double change going into the last 20: Taiwo Awoniyi and Cedric Teuchert replaced Becker and Haraguchi. On 74 minutes, Dominik Martinovic was in the right place at the right time to clear off the line from Robin Knoche's shot after an excellent training ground routine at a corner kick. With fresh legs in the forward areas, it was Union who looked stronger going into the final sprint. Awoniyi sent Prömel in on the Mannheim defence with six minutes to go but Odonkor made an exceptional recovery. Oczipka had run his race after 89 minutes with Gießelmann coming in as the referee indicated two minutes of additional time. Union needed one chance to take home the victory, but substitutes Teuchert and Awoniyi couldn't put in the winner after a scrappy situation inside the Mannheim penalty box.

The in-form Awoniyi needed just four minutes after Benjamin Brand started the additional 30 minutes to put Union in the driving seat. A quick break of the ball fell into the striker's path and he finished off emphatically from the edge of the box – his 12th goal of the campaign in all competitions for 1. FC Union Berlin. As the home side looked dead on their feet, Union passed up the chance to score a third as Behrens fired wide in the 102nd minute. In the immediate stoppage of play, the skipper was wrapped up in cotton wool following his exertions and replaced by Polish wing-back Pawel Wszolek who joined in the summer from Legia Warsaw. Although it was a tense evening in Mannheim, the visitors from Köpenick made sure of the victory as Behrens slammed home with a few minutes to play in extra-time. Union will go into the draw for the German Cup Last 16 – returning to the third round after a one-year absence. 

When the squad returns to the capital, 1. FC Union Berlin and Urs Fischer will look forward to Saturday's Bundesliga encounter against Bayern Munich at the Stadion An der Alten Försterei.