Mauro Icardi took his Serie A goal tally to a league-leading 14 with a brace in a 3-0 win over Lazio that gave Inter Milan's fans some unexpected festive cheer.
Lazio travelled to the San Siro looking for a win that would have pushed Simone Inzaghi's men up to second at five points behind Juventus.
But the visitors, who won both fixtures against Inter last season, failed to make the most of a promising opening half when Ciro Immobile and Felipe Anderson came close to breaking the deadlock.
Lazio paid the price in 11 second-half minutes, first when Argentina midfielder Ever Banega pounced on a defensive mistake by Sergej Milinkovic-Savic to beat Federico Marchetti with a searing strike into the top corner.
Icardi headed Inter's second two minutes later. The Argentine moved two goals past Roma striker Edin Dzeko and Andrea Belotti of Torino in the Serie A goal standings just nine minutes later with his second of the night.
He should have had his hat-trick, but was stopped by Marchetti on 71 minutes then saw a late strike hit the woodwork.
Inter remain in seventh place but their ninth win of the campaign and fourth in six games under new coach Stefano Pioli closed the gap on Juventus, who will face AC Milan in Doha for the Italian Super Cup on Friday, to 12 points.