Jamal Musiala celebrated turning 20 with his 11th goal of the Bundesliga season as Bayern Munich returned to top spot by crushing title rivals Union Berlin 3-0 in wintry Bavaria.

A dusting of snow covered the Allianz Arena pitch at kick-off, and more fell during the game, but there was nothing flaky about the hosts.

Goals from Eric Maxim Choupo-Moting, Kingsley Coman and Musiala meant they led 3-0 at half-time against a team who began the game on the same points total as Bayern.

The outcome meant Bayern nudged ahead again in the title race, going above Borussia Dortmund on goal difference, with surprise interlopers Union now trailing the top two by three points.

Bayern were rewarded for early dominance in the 31st minute when Choupo-Moting at the far post looped a header across goal and into the corner from Coman's right-wing cross.

That was the striker's ninth goal of the season, completing a career set for the former Hamburg, Schalke and Mainz man, who has now netted against every current Bundesliga team.

It was 2-0 in the 40th minute when Thomas Muller's clever pass played in Coman who danced around goalkeeper Frederik Ronnow before burying a low finish.

Two soon became three, with Bayern on easy street as they struck again in first-half stoppage time, Muller the provider once more when his cutback from the byline on the right found Musiala to smash in from close range.

Sadio Mane came off the bench midway through the second half, replacing Choupo-Moting, as the former Liverpool forward appeared for the first time since suffering a leg injury in November that ruled him out of Senegal's World Cup campaign.

Mane teed up a glorious chance for Muller, with the veteran's shot hitting the head of goalkeeper Ronnow and going over the crossbar.

Fellow substitute Serge Gnabry lashed just wide as Bayern threatened to run riot, but they settled in the end for three.

What does it mean? Clinical Bayern, sorry state of Union

From kick-off, this never had the flavour of a top-of-the-table battle, with Bayern exerting a firm grip long before their breakthrough arrived.

There has been a slip in standards from Julian Nagelsmann's team of late, but this was more ruthless, and it means Bayern remain unbeaten against Union Berlin in the Bundesliga (W5, D3). They have only faced two other teams, Rot-Weiss Oberhausen and SV Darmstadt, on as many occasions in the Bundesliga (both 8 times) without ever losing.

Across the piece, Union had only three shots and none of those tested Yann Sommer. The result means Bayern remain the only German top-flight side Union have never beaten, and on this evidence it will be a good while before that changes.

Muller makes his point

Muller was substituted early in the first half last week, sacrificed for defender Joao Cancelo after Dayot Upamecano was sent off in the 3-2 defeat to Borussia Monchengladbach. The captain was said to be unhappy, but here he showed his value to the team, setting up two goals, having a team-high three shots on target, and prowling with familiar intent. A statement performance.

Union let it slip

After just about protecting their goal for the first 30 minutes, Union then folded. Although they had only conceded 24 goals in 21 Bundesliga games prior to this, seven of those goals had come in the closing 15 minutes of the first half in those fixtures.

Here came three more, meaning only Hertha Berlin (11) have shipped more goals in this stage of games this season.

Bayern were rampant, but Union's defending left plenty to be desired.

What's next?

Bayern travel to tackle struggling Stuttgart next Saturday, while Union will look to reignite their challenge when they host Koln on the same day.