The champions took up where they left off. In their final game before the month long pause, the Bavarians won 1-0 at Hannover to go eight points clear of second placed Dortmund who lost 2-1 in Cologne.
Before Christmas, Bayern had Thomas Muller to thank for the winning goal. Against Hamburg, Lewandowski was the star man. The 27-year-old netted a first-half penalty but Bayern were pegged back when Hamburg levelled courtesy of an Aaron Hunt free kick.
Lewandowski hit the winner on the hour mark. It was the Poland international's 17th league goal of the season. "In the first half we controlled the game but we were asleep when Hamburg had their free-kick," said Lewandowski. "Fortunately we still won. We know we still need some time after the winter break but the main thing was to take three points in the first match of the year."
Elsewhere in the Bundesliga, Darmstadt moved clear of the relegation zone with a 2-1 win at bottom of the table Hannover. Hugo Almeida gave the hosts the lead after 10 minutes but Sandro Wagner scored either side of half-time to secure a precious three points.
Hoffenheim are second from bottom after a 1-1 draw with Bayer Leverkusen.
In England, Leicester City went top after beating Stoke City 3-0. Danny Drinkwater got the opener for Claudio Ranieri's men just before half-time. Jamie Vardy added the second after 66 minutes and Jose Leonardo Ulloa added the gloss three minutes from time. Arsenal will leapfrog Leicester City provided they beat Chelsea on Sunday at the Emirates.
Tottenham Hotspur consolidated their place in fourth with a 3-1 victory at Crystal Palace. Manchester United are five points behind in fifth after losing 1-0 at home to Southampton. New signing Charlie Austin got the winner in the 87th minute. United's players were booed off the pitch by the fans at Old Trafford. The defeat will increase the pressure on the manager Louis van Gaal who has come under fire for his side's lack of goals and poor performances.
The former Chelsea boss Jose Mourinho as well as the Bayern Munich manager Pep Guardiola have been touted as possible replacements for the Dutchman.