Juventus moved closer to a fifth successive Serie A title with a 4-1 derby victory at Torino, while Gianluigi Buffon set a new league record for the longest run without conceding a goal at 973 minutes.
Buffon's historic run was ended by Andrea Belotti's penalty after 10 clean sheets, but Juventus eased to victory on Sunday.
Juve's top goalscorer Paulo Dybala, who returned from a calf injury to start, lasted only half an hour before limping off but Massimiliano Allegri's side have now won 19 of their last 20 league matches, a run that started with a 2-1 win against Torino at the end of October.
Tomas Rincon's long-range strike put the visitors into a shock 10th-minute lead but Higuain struck twice in the second half and Omar El Kaddouri added gloss to the scoreline in injury-time.
AC Milan drew 1-1 at home to Lazio after Carlos Bacca cancelled out Marco Parolo's early header, leaving both sides looking unlikely to qualify for European football next season.
Carpi moved out of the relegation places with a 2-1 win at bottom side Verona, Kevin Lasagna's free-kick giving his side a vital three points in their survival battle.
Luigi De Canio's first game as Udinese coach ended in a 1-1 draw at Sassuolo after Duvan Zapata's opener was followed by Matteo Politano's header and Chievo moved into the top half of the table with a 1-0 win at Sampdoria.
