Gladbach dominated the first half and missed a string of chances, with Freiburg goalkeeper Alexander Schwolow denying Plea and Lars Stindl in quick succession as the home side defended desperately.
Bayern remained unruffled by the two-month break due to the novel coronavirus pandemic and beat Dortmund last month to overcome the last major obstacle en route to a 29th Bundesliga title since the introduction of the top division in 1963.
Fresh-faced Germany were made to work harder than expected in their 3-2 victory over Australia in their Confederations Cup Group B debut on Monday with the world champions' young squad still adjusting to tournament life.
The Germans have lost just once in 23 games since their Euro 2016 semi-final defeat, cruising through the qualifiers with 10 wins in 10 matches.
Moffi penalty gives Lorient 1-0 win over Monaco.
In-form Borussia Moenchengladbach struck three times in 14 minutes in the second half to floor champions Bayern Munich 3-1 on Saturday and inflict their first Bundesliga defeat of the season.
A dramatic game featured missed chances, defensive howlers, scuffles and two video reviews, one producing a highly controversial outcome in the second half.
The Arsenal forward broke the record just five minutes into the match, taking his tally to 38 with his national side at the Kazan Arena, Kazan.
Thomas Meunier volleyed a spectacular last-minute goal to give Paris St Germain a 2-1 win at FC Basel, which took them into the last 16 of the Champions League on Tuesday.
Manchester City, who crushed Gladbach 4-0 at home in September, are in second place in the group on seven points, three ahead of the Germans, and can wrap up qualification with victory in Germany.
"We are pleased with the win, the many chances and the 70,000-plus spectators."
Thomas Mueller and Thiago Alcantara struck twice as Bundesliga leaders Bayern Munich thumped Werder Bremen 5-0 on Saturday to open an eight-point gap at the top with their first win in three games. The Bavarians, who claimed one point from their previous two matches, terrorised visiting Werder with Kingsley Coman setting up three goals in an eye-catching dress rehearsal for the Champions League last-16 second leg against Juventus next week. "It may look easy ... but it was not," said Bayern coach Pep Guardiola. "It was important to win after losing to Mainz 05 (last week). "As for Kingsley, he is a young player but today he showed his quality. We will need such a player on Wednesday." Guardiola can also count on Mario Goetze again after the attacking midfielder made his comeback from a four-month injury layoff.
Leaders Bayern Munich twice surrendered the lead in a 2-2 Bundesliga draw at 10-man Eintracht Frankfurt on Saturday and Borussia Moenchengladbach missed two penalties in a goalless draw against Hamburg SV.
Europa League favourites Manchester United secured a 1-1 draw on a threadbare pitch at Rostov, while Olympique Lyonnais beat AS Roma 4-2 helped by a fine individual goal from Nabil Fekir in their last 16, first leg ties on Thursday.
Tottenham Hotspur's Europa League hopes were crushed by mid-table Belgian side Gent, who booked their spot in the last 16 with a 2-2 draw at Wembley on Thursday as the hosts paid the penalty for Dele Alli's first-half red card.
Bayern Munich's party was wrecked by Borussia Moenchengladbach who hit back for a 1-1 draw at the Allianz Arena on Saturday, forcing the Bavarians to wait at least a week to clinch a fourth straight Bundesliga title.
In-form Borussia Moenchengladbach struck three times in 14 minutes in the second half to floor champions Bayern Munich 3-1 on Saturday and inflict their first Bundesliga defeat of the season.
Borussia Dortmund stayed top of the Bundesliga by beating Augsburg 4-3, while titleholders Bayern Munich were thumped 3-0 at home by Borussia Moenchengladbach.
Here is a round-up of results from the European League matches played on Wednesday
Manchester City's quadruple bid remained intact as Ilkay Gundogan and Kevin de Bruyne secured a 2-0 win at Everton in their FA Cup quarter-final clash
Unai Emery's side were heading for a demoralising defeat, three days after losing meekly to Sheffield United in the Premier League, but substitute Pepe's late intervention kept the Gunners top of Group F with a maximum nine points.
News of all that's transpired on and off the football field
Images from football matches played in the La Liga, Serie A and Bundesliga on Saturday.
The dazzling Lionel Messi returned from illness to score yet another double to help Barcelona ease into the knockout stages of the Champions League for a 13th successive year with their 2-0 win at Celtic on Wednesday.
News of all that's transpired on and off the football field
Juventus striker Gonzalo Higuain again showed his killer instinct with two expertly-taken goals in a late 3-1 win at Torino after their less illustrious neighbours had scored first and dominated the Serie A game on Sunday.
Sweden striker Zlatan Ibrahimovic crowned a triumphant homecoming with a second-half goal as Paris St Germain crushed Malmo 5-0 on Wednesday to book a place in the last 16 of the Champions League.
News of all that's transpired on and off the football field
News of all that's transpired on and off the football field
Images from the UEFA Champions League matches played across Europe on Wednesday
Photos from the Champions League matches played on Wednesday.