Real Madrid beat Rayo Vallecano 1-0 to remain nine points clear at the top of La Liga; Atletico Madrid, Valencia also registered wins.
In September, Lionel Messi signed a free agent contract with PSG, while Ronaldo joined Juventus from Real Madrid in 2018.
Barcelona are in talks with Wolves over a move for Adama Traore.
The Spanish football league is taking technology to the next level by introducing goal probability ratio.
The Frenchman will spend the rest of the season with the Spanish club, hoping that the move will allow him to play regularly for the first squad.
La Liga giants Real Madrid and Barcelona had two very contrasting weekends after the latest round of La Liga matches.
Dembele, who signed for 140 million euros from Borussia Dortmund in 2017, will be free to leave when his contract expires in the summer.
Torres joined Barcelona last week for a sum of around 55 million euros, and he was officially unveiled to fans at Camp Nou on Monday.
The January transfer window is now open, and there is expected to be plenty of movement of players from a number of La Liga clubs.
La Liga returned after the Christmas break this weekend, and Spain's giants had contrasting fortunes in their respective fixtures.