Hamburg SV's miserable run continued when the Bundesliga's only ever-present side conceded three first-half goals on the way to a 3-0 home defeat against Hertha Berlin, keeping them in the relegation zone.
Colombian forward Adrian Ramos missed a penalty but also scored two goals as Hertha handed Hamburg their sixth defeat in a row.
The league's second top scorer Lewandowski, whose double took his tally to 13, set Dortmund on the way when he struck with a sublime right-foot finish from just inside the penalty area after being set up by Marcel Schmelzer in the 26th minute.
Mkhitaryan skipped two tackles before scoring with a low shot from outside the area to make it 2-0 before halftime.
Defender Manuel Friedrich tapped in his first Dortmund goal after the break and Mkhitaryan and Lewandowski completed the rout as Dortmund ran amok against a ragged Werder defence.
Levent Aycicek grabbed a late consolation for the hosts who are 13th with 20 points, too close to the drop zone for comfort. Nuremberg occupy the relegation playoff spot with 17 points.
Hamburg stayed one point below them in 17th after a series of defensive blunders left them in disarray against Hertha.
They had a let-off when goalkeeper Rene Adler brilliantly saved a Ramos penalty in the 15th minute, only for the Colombian to outjump the defence from the resulting corner to produce a goalbound header that was turned in by Sami Allagui.
Ramos was again too powerful when he nodded the second eight minutes later. He then showed his ability with his feet as he slotted home a third on the counter attack seven minutes before the break.
First-half goals from Eintracht Frankfurt's Johaness Flum, Alexander Meier and Stefan Aigner earned a 3-0 win over bottom club Eintracht Braunschweig, lifting them to 12th.
Sixth-placed VfL Wolfsburg scored all their goals in the second half as they beat Mainz 05 by the same score.
- Sports & Recreation
- Hertha Berlin
- Adrian Ramos
- Hamburg SV
- Marcel Schmelzer