* Supersub Alcacer scores 10th league goal
* Reus grabs his ninth goal with first-half penalty
* Dortmund are seven points clear at the top
* Coach Favre unbeaten in 13 league games (Updates with details)
BERLIN, Dec 1 (Reuters) - Bundesliga leaders Borussia Dortmund earned a hard-fought 2-0 victory over Freiburg with goals from Marco Reus and Paco Alcacer on Saturday to open up a seven-point gap at the top of the Bundesliga with their fourth consecutive league win.
The result also meant Lucien Favre became the first Dortmund coach to be unbeaten in his first 13 consecutive league games.
The Ruhr valley club are top on 33 points, with Borussia Moenchengladbach second on 26 and in action at RB Leipzig on Sunday. Champions Bayern Munich are third on 24 after beating Werder Bremen 2-1.
Dortmund captain Reus fired in a 40th-minute penalty for his ninth league goal to put the aggressive hosts ahead and inject some life into the crowd, largely silent until that point in protest over the league’s scheduled Monday night matches.
But Freiburg proved difficult opponents, closing down spaces quickly and pinning the hosts, who have the Bundesliga’s best attack, well outside the box, while also hitting the woodwork late in the first half through Jerome Gondorf’s free kick.
Dortmund, who booked their Champions League knockout stage ticket this week, had lots of possession but struggled to find a way past the Freiburg defence, with Lukasz Piszczek also hitting the crossbar for the hosts.
The visitors’ resistance ened when supersub Alcacer, who had come on in the 70th minute, drilled in from close range after fine early work from Jadon Sancho to grab his 10th league goal and secure the three points. (Reporting by Karolos Grohmann; editing by Clare Fallon and Ken Ferris)