Diego scored on his first start for seven weeks as Atletico Madrid cruised to victory over Getafe.
In Sunday's other games, Valencia let a lead slip away for the fourth consecutive home game as they drew with Levante.
And Real Sociedad hammered Rayo Vallecano while Espanyol held Villarreal to a goalless draw.
Atletico Madrid cruised to a comfortable 3-0 win over Getafe as Diego scored on his first start for seven weeks.
Eduardo Salvio put the hosts in front midway through the first-half as he brilliantly looped a header over Miguel Angel Moya from Filipe Luis' cross.
Diego, back from a leg injury, then made it two just after the hour mark as his initial header off the bar rebounded kindly for him to tap home at the second attempt.
And Radamel Falcao wrapped up the three points 13 minutes from time with another calm finish from Juanfran's cross for his 20th league goal of the season.
Valencia let a lead slip away for the fourth consecutive home game as Arouna Kone's second-half strike earned local rivals Levante a 1-1 draw at the Mestalla.
Jonas Goncalves rounded off a fine team move to give the hosts the lead 10 minutes before half-time, but Levante were level eight minutes after the break as Valdo headed Jose Barkero's cross into the path of the Ivorian who rifled home his 11th league goal of the season.
Both sides had great chances to win the game in the final 10 minutes as Kone stabbed Pedro Botelho's cross inches wide before substitute Paco Alcacer headed straight at Gustavo Munua with the goal at his mercy.
Valencia have now only won once in six league matches at home in 2012.
Real Sociedad moved eight points clear of the relegation zone and to within a point of Rayo Vallecano with a comprehensive 4-0 victory at the Anoeta to end a three-game losing run.
Imanol Agirretxe opened the scoring for the hosts after six minutes and Philippe Montanier's side doubled their lead just after the half hour mark through David Zurutuza.
Sociedad wrapped up the points with two goals in a matter of minutes soon after half-time with goals from Frenchman Antoine Griezmann and Arsenal loanee Carlos Vela.
Villarreal remain undefeated in three matches under new coach Miguel Angel Lotina following a 0-0 home draw with Espanyol.
Villarreal have lost only twice at home in the league and they showed why at El Madrigal in a disappointing encounter with very few chances.
The Yellow Submarine are now just four points clear of the bottom three while Espanyol stay in seventh spot.