Koke scored the first goal in the 69th minute from a pass by Deivid Souza. He added his second in the 90th.
Also, Benni McCarthy, Pepe Ferreira and Lucho Gonzales scored a goal each to give FC Porto a 3-0 victory over Nacional.
Porto leads the league with 54 points, two more than Sporting and five more than Benfica.
On Saturday, Benfica beat Amadora 2-1 with goals by Laurent Robert and Fabrizio Miccoli.
Guimaraes upset Setubal 4-0 Friday.
Marek Saganowski scored three goals and Cleber Lima added the other.
Borussia Moenchengladbach beat Arminia Bielefeld 2-0 to rise to sixth place.
Eintracht Frankfurt wasted several opportunities and had to settle for a 1-1 draw against visiting Wolfsburg.
Defender Marcell Jansen, hoping to secure a place in Germany's World Cup squad, crowned a stellar performance by scoring Moenchengladbach's first goal in the 34th minute. Wesley Sonck pounced on a rebound to score the second in the 65th.
In Frankfurt, Mike Hanke, another World Cup hopeful, drove home a free kick in the 58th to stun the dominating hosts.
But Ioannis Amanatidis saved a point for Frankfurt after Wolfsburg goalkeeper Simon Jentzsch could not hold on to a powerful header by Marko Rehmer.
Frankfurt remained 12th, one place above Wolfsburg.
Salomon Kalou scored twice and Feyenoord continued chasing leader PSV Eindhoven with a 3-0 win over FC Utrecht
With seven games remaining, Feyenoord is seven points behind PSV, which beat Heerenveen 4-1.
AZ Alkmaar is 11 points back after a 2-0 win Friday over NEC Nijmegen. Fourth-place Ajax, 20 points back, crushed Sparta Rotterdam 6-0 with a hat trick from Klaas Jan Huntelaar, the league's top scorer.
PSV and Ajax play difficult second-leg away matches in the Champions League this week. PSV must overcome a 1-0 deficit at Lyon, while Ajax heads to Inter Milan at 2-2.
Marseille held Paris Saint-Germain to a 0-0 draw despite fielding a reserve team against its biggest rival.
"The prevailing sentiment is shame," PSG president Pierre Blayau said. "I beg PSG fans to forgive us for our performance."
The Marseille youngsters defended aggressively to prevent PSG's veterans from creating chances.
"It's almost like a victory even if we just collect one point," Marseille assistant coach Albert Emon said. "I think the kids gave everything. They'll sleep well tonight."
Marseille is in fifth place in the French league with 44 points from 29 matches.
Auxerre drew 1-1 with Troyes to remain in fourth place with 47 points.
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