Lyon have 19 points, two behind third-placed Caen after they surprisingly lost 2-0 at home to Nantes with Yacine Bammou and Adrien Thomasson on the scoresheet.
At Stade Gerland, France midfielder Valbuena was instrumental throughout.
He sent in a cross after 18 minutes and Spaniard Sergi Darder was on hand to finish off for his first Ligue 1 goal.
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Lyon continued to press against lowly Toulouse and it was no surprise when Valbuena, playing in the midfield 'hole' rather than on the wing, made the game safe on 69 minutes with the cleanest of strikes.
Maxwell Cornet added the third goal in injury time.
Champions Paris St Germain again set the pace in France and lead second-placed Angers and Caen by five points ahead of hosting fifth-placed St Etienne on Sunday.
Shock high fliers Angers welcome Guingamp on Saturday.
(Writing by Mark Meadows; Editing by Tony Jimenez)
