Bundesliga leaders Borussia Dortmund got second-half goals from supersub Paco Alcacer and Lukasz Piszczek to edge past Mainz 05 2-1 on Saturday and open up a seven-point gap at the top.

Their seventh win in the last eight league games lifted them to 30 points, seven ahead of second-placed Eintracht Frankfurt. Champions Bayern Munich are fifth on 21 after a 3-3 draw against promoted Fortuna Duesseldorf.

Spaniard Alcacer, whom Dortmund agreed to sign permanently from Barcelona on Friday, snatched his ninth goal of the campaign in the 66th minute, two minutes after coming on, to lead the scorers' list in the Bundesliga.

Eight of those goals have come in substitute appearances.

Dortmund's joy did not last long with Mainz's Robin Quaison levelling four minutes later.

Dortmund stayed focused and kept up the pressure until defender Piszczek curled in a shot from the edge of the box in the 76th to secure the three points for the Bundesliga leaders.

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