The Bundesliga race for Champions League places heated up on Saturday as Borussia Dortmund won 2-0 at Union Berlin to stay fourth and RB Leipzig beat Bochum 4-1 to keep pace a point behind.

The unrelenting form of league leaders Bayer Leverkusen and surprising Stuttgart, who won 3-2 at Wolfsburg in Saturday's late match to solidify their grip on third, has left Champions League regulars Dortmund and Leipzig battling it out for fourth.

Karim Adeyemi's 41st minute goal, his first of the season, put Dortmund on course for victory before Chelsea loanee Ian Maatsen added another in stoppage time to lock up three points that may ease pressure on under-fire manager Edin Terzic.

Hosts Union Berlin were unbeaten at home since early November, and their goalkeeper Frederik Ronnow kept Dortmund at bay until Adeyemi took two touches before unleashing a long-range effort which thundered in off the crossbar.

"We were a little bit sleepy at first," Adeyemi said.

"But then we played ourselves into the match and had a solid performance," he added.

Leipzig, who visit Real Madrid on Wednesday in their Champions League last 16 second leg, stayed on Dortmund's heels, scoring three goals in four second-half minutes at Bochum.

Maximilian Wittek's opener had help from Leipzig goalkeeper Peter Gulacsi, the Hungarian knocking a free-kick into his own net.

Xavi Simons' strike after 15 minutes was chalked off for offside, but Leipzig drew level through a long-range Dani Olmo strike on the half hour.

Openda came on for Leipzig after 65 minutes and scored three minutes later, blasting in on the counter for his 17th goal of the season.

An own goal and a Yussuf Poulsen strike on the 71 and 72-minute marks ensured Leipzig would depart Bochum with the three points.

The victory was just Leipzig's third win in nine games this calendar year.

"We left too many points behind since winter -- so this win will do us good," Leipzig's Poulsen told reporters.

Defender David Raum said "we can fly to Madrid feeling a bit more free" after the result.

Mired in mid-table, Bochum have impressed at their Ruhr Stadium this season, losing just two of 12 matches. They had beaten Bayern Munich 3-2 in their last home game.

Stuttgart's revival this season continued with Serhou Guirassy scoring a double as they won at Wolfsburg.

Playing his 18th game of the season, Guirassy headed in his 19th goal after just 14 minutes to give Stuttgart the lead.

Wolfsburg's Joakim Maehle finished off a beautiful team goal five minutes into the second half but Stuttgart hit back immediately, Guirassy converting a penalty to bring up goal number 20 this campaign.

Josha Vagnomann added a third before Wolfsburg's Lukas Nmecha scored a late consolation, bringing the visitors within four points of second-placed Bayern.

Mainz drew 1-1 with Borussia Moenchengladbach at home, Jonathan Burkardt's 12th-minute strike cancelled out by a 55th minute-goal from visiting midfielder Nathan Ngoumou.

Eintracht Frankfurt won 2-1 at Heidenheim to tighten their grip on sixth.

An own goal from Benedikt Gimber and a Niels Nkounkou strike helped the Eagles secure their first win since January, with Marvin Pieringer grabbing a consolation for the hosts.

Augsburg scored five goals in the opening half an hour to thump rock-bottom Darmstadt 6-0.

Phillip Tietz and Ermedin Demirovic both scored doubles, with promoted Darmstadt 12 points from safety and looking on course for an immediate return to the second division.

League leaders Bayer Leverkusen head to Cologne on Sunday and can extend their lead atop the table to 10 points with a win after Bayern were held 2-2 at Freiburg on Friday.