Birthday boy Musiala helps Bayern reclaim Bundesliga lead
Bayern now top the Bundesliga, tied with Borussia Dortmund on 46 points. Union are third, three points behind.
First-half goals from Eric Maxim Choupo-Moting, Kingsley Coman and Musiala, on his 20th birthday, put Bayern into a comfortable position against the overachieving Berliners.
In another positive for Bayern, the champions welcomed back Sadio Mane who came on as a substitute after an injury absence of nearly four months.
A pre-match blizzard failed to cool Bayern's fluency, with the home side forcing Union into several last-ditch saves in the opening moments.
Bayern striker Eric Maxim Choupo-Moting got the home side on the scoreboard after 31 minutes, heading in a lofted pass from Kingsley Coman.
Union almost hit back five minutes later when Tunisia international Aissa Laidouni blasted just past the upright after a nice pass from Sheraldo Becker.
Bayern doubled up immediately afterwards, Thomas Mueller chipping the Union defence with his back to goal to send Coman through one-on-one with Union goalie Frederik Ronnow. The France forward rounded Ronnow and slid the ball into the net.
Mueller was the provider again in first-half injury time, setting up Musiala to give Bayern a 3-0 halftime lead.
Bayern took the sting out of the match after halftime in pursuit of just their third league win from seven matches in 2023, giving away few chances to the outclassed visitors.
Mane came off the bench in the 65th minute for Coman, his first appearance since sustaining a leg injury which ruled him out of Senegal's campaign at the World Cup in Qatar.
Mane put Mueller through on goal just five minutes later, but goalkeeper Ronnow headed the veteran forward's shot over the bar.
Bayern manager Julian Nagelsmann said the "style and manner" of the victory pleased him more than just claiming the three points.
"As I've said before, today won't decide the championship, but the style and manner we did in was good."
Union's Rani Khedira said the team's recent exertions, including Thursday's 3-1 Europa League defeat of Ajax, played a role in his team's performance, but said the side "wasn't looking for excuses."
"We were too deep, a bit too passive and maybe a little intimidated."
Union manager Urs Fischer said "there was a big difference in class" between the sides.
"The second and third goals before the break annoyed me. When you invite Bayern, then they'll say thanks."
The victory means Bayern overtake Dortmund who went three points clear with a 1-0 win at Hoffenheim on Saturday. The Bavarians now sit ahead of the Westfalians on goal difference.
Union finish the round in third, one point ahead of fourth-placed RB Leipzig.
Azmoun snatches draw
A second-half goal from Iran striker Sardar Azmoun helped Bayer Leverkusen grab a 1-1 draw at Freiburg earlier on Sunday.
A goal from free-kick specialist Vincenzo Grifo had put Freiburg into a first-half lead and on course for a valuable three points in their top-four bid, but Azmoun's first goal in Leverkusen colours meant the honours were shared.
Grifo credited the "incredible quality" of the guests and said "you can't always win, so we are reasonably happy with the point."
His coach Christian Streich echoed the sentiments, saying "handy and lively Leverkusen were really good"
"I'm happy with the draw. It's a good point for us."
Alonso said he was "satisfied with the performance" but admitted "we wanted a little more".
