BERLIN: Borussia Dortmund scored in each half to ease past Mainz 05 2-0 on Sunday and stay five points off leaders Bayern Munich with eight matches left in the season.

The Ruhr valley club were never troubled in the game, overshadowed by the death of a fan in the tribunes from an apparent heart attack, and should have scored more goals were it not for Mainz's Loris Karius.

The keeper single-handedly kept the scoreline low, denying Dortmund on more than six occasions with a string of outstanding saves as fans kept quiet, stunned by the sudden death among them.

Dortmund said a second fan had also suffered a heart attack but was resuscitated and in a stable condition in hospital.

"During the game there was a tragic incident where two people had to be resuscitated. One person did not make it," Dortmund said in a brief statement. "We are filled with grief and our thoughts are with the families."

On the pitch Marco Reus confirmed his good form with a 30th minute strike and Shinji Kagawa doubled their lead as Dortmund climbed to 61 points, with Bayern on 66 after Saturday's 5-0 demolition of Werder Bremen.

Bayer Leverkusen edged past Hamburg SV 1-0 courtesy of an Albin Ekdal own goal for their first league win in four matches as coach Roger Schmidt returned to the Bundesliga from suspension.

Leverkusen had managed just one point in their last four league games, with Schmidt having missed the previous three following a ban for dissent in their 1-0 loss to Borussia Dortmund in February.

The result offered Schmidt some respite, following their mid-week loss to Villarreal in the Europa League, lifting Leverkusen to seventh, a point off the European spots.

Leverkusen keeper Bernd Leno pulled off several spectacular saves to protect their lead and make an impression as he battles for a spot on Germany's Euro 2016 squad.

The hosts were left with 10 men in stoppage time after Tin Jedvaj was sent off for complaining to the referee but Hamburg, who have won just once in their last five matches, could not find a late goal, slipping to 12th on 31 points.