Substitute Jose Callejon slotted in a third against his former club and Higuain completed his hat-trick a minute from time as Real condemned Espanyol to their first defeat at home.
An injury-plagued Barcelona moved into first place with 14 points as Adriano gave them their first away win of the season.
Cesc Fabregas and Andres Iniesta were among the midfielders in the treatment room while neither Carlos Puyol nor Gerard Pique started in defence.
Barca don't have a good record against Sporting and drew there last season but Adriano gave them the lead, knocking in a rebound after a Xavi Hernandez shot came back off a post.
While Barca had almost total control of the ball they struggled to convert it into further goals against an organised Sporting, whose only shot of note was a Roberto Canella drive which keeper Victor Valdes parried before halftime.
Eric Abidal went off injured to add to Barca's defensive worries but they never looked likely to concede and the main danger to the Sporting goal came from a Lionel Messi header which keeper Juan Pablo caught.
"We played a strong Sporting who were very deep and worked together well. There was no space because they closed it down," said Barcelona coach Pep Guardiola.
Unfashionable Levante are behind Barcelona only on goal difference after a Juanlu Gomez goal gave them a 1-0 win over former leaders Real Betis.
Malaga are a point behind the leaders after a superb overhead kick in injury time from Julio Baptista completed a spectacular turnaround over Getafe 3-2.
Valencia beat Granada 1-0 and Atletico Madrid drew 0-0 with Sevilla.
Two penalties from Tomer Hemed gave Mallorca a 2-2 draw away to Osasuna.
- AAP