Borussia Dortmund advanced to the DFB Cup round of 16 with a penalty shootout win over Eintracht Frankfurt on Tuesday after a 1-1 draw.

Frankfurt went ahead in the seventh minute when former Dortmund winger Ansgar Knauff finished from Mario Gotze's through ball.

Frankfurt's strong start unsettled the visitors, who struggled to find rhythm despite having more possession. Gregor Kobel twice denied Fares Chaibi and Ritsu Doan from distance before halftime.

After the break, Dortmund raised the intensity and leveled three minutes into the second half. Julian Ryerson's low cross from the right found Julian Brandt at the far post for the equalizer. Frankfurt nearly restored the lead when Doan hit the crossbar from 20 meters, while substitute Can Uzun forced another save from Kobel late on.

The tie was decided on penalties. Dortmund's takers -- Brandt, Beier, Sabitzer and Ryerson -- all converted, while Doan sent his attempt over and Kobel saved from Chaibi to clinch a 4-2 shootout win.

The result sends Dortmund into the last 16 and extends its unbeaten run in all competitions. Frankfurt, disciplined defensively throughout, now hosts Heidenheim in the Bundesliga next weekend, while Dortmund visits Augsburg on Friday.

"The game had to be decided in a penalty shootout because both teams gave everything. Frankfurt made it very difficult for us, and in the end, a bit of luck was on our side. We are through, and that is what matters," said Kovac.

Elsewhere in the second round, Hamburg beat 10-man Heidenheim 1-0 courtesy of Tim Siersleben's goal, and Hertha Berlin eased past SV Elversberg 3-0. Second-division Holstein Kiel edged Wolfsburg 1-0, and Christoph Baumgartner's brace guided Leipzig to a 4-1 win over Energie Cottbus. Borussia Monchengladbach defeated Karlsruher SC 3-1, VfL Bochum won 1-0 at Augsburg, and St. Pauli equalized in stoppage time of extra time before beating Hoffenheim 8-7 on penalties (2-2).