US teenager Christian Pulisic scored his first Bundesliga goal on Sunday as Borussia Dortmund kept some pressure on leaders Bayern Munich with a 3-0 win over 10-man Hamburg.

Dortmund bounced back from the heart-break of their last-gasp 4-3 defeat at Liverpool on Thursday, which ended their Europa League campaign at the quarter-final stage, with a first win over Hamburg in five league games having last beaten Bruno Labbadia's side back in September 2013.

Pulisic only turns 18 in September, but having played his first German league game in January, the left winger made his senior international debut for the USA in March.

He has now scored his first Bundesliga goal on only his third start after being promoted from the Under-17 side by head coach Thomas Tuchel in the winter break.

Dortmund look to have uncovered another star just as they seem set to lose one.

Reports on Sunday in both the German and UK media suggest defensive midfielder Ilkay Gundogan is set to join Manchester City for the start of next season.

But Dortmund stayed in the hunt for the German league title as Colombia striker Adrian Ramos scored twice at Signal Iduna Park.

Hamburg were reduced to ten men early in the second half when goalkeeper Rene Adler was shown a straight red after bringing down Shinji Kagawa.

After a great pass from Dortmund captain Mats Hummels, Pulisic gave Dortmund the lead with a strike which beat Adler at the near post on 38 minutes.

"It's an amazing feeling to get my first goal. Mats put in a great pass to set me up," said Pulisic.

"It's hard to put into words what it felt like to score."

Ramos then made it 2-0 when he also put in a superb strike across the face of the Hamburg goal on 44 minutes.

Hamburg had Adler sent off on 52 minutes and Ramos added his second on 86 minutes when Japan's Kagawa put in the final pass.

Dortmund now have the chance to book their place in the German Cup final when they play Hertha Berlin away in the semi-final on Wednesday.

"We were all very sad (after the Liverpool defeat), but the coach told us we have to go on and now we'll have to wait and see what happens in Berlin," added Pulisic.

Dortmund's win trims Bayern's lead to seven points with only four games left after Pep Guardiola's side beat Schalke 3-0 at home on Saturday.

Poland hot-shot Robert Lewandowski netted twice in Munich to leave him as the league's top scorer with 27 Bundesliga goals this season.

Later on Sunday, Cologne came from 2-0 down to pull off a stunning 3-2 win at Mainz.

The hosts would have climbed to fifth and closing on a Europa League place for next season after goals by striker Jhon Cordoba and defender Leon Balogun.

But Cologne roared back at Mainz's Coface Arena with goals from Marcel Risse and Milos Jojic before French striker Anthony Modeste netted the dramatic winner in the dying stages.

The win moves Cologne up to 10th while Mainz remain sixth.