Real Madrid reduced the gap at the top of the Primera Division to eight points ahead of next weekend's El Clasico as
Riki had given the visitor a shock lead on 15 minutes but Real was level seven minutes later when Ronaldo scored from the penalty spot after
And the host was in cruise control by half-time as
Pepe headed in the fourth 25 minutes from time after Xabi Alonso's free-kick, before Ronaldo completed his hat-trick with another penalty after Evaldo had been harshly adjudged to have handled Kaka's cross.
Two goals in the opening 20 minutes were enough to hand Granada its first victory of the season as it withstood a second-half onslaught from
Iago Aspas quickly reduced the arrears for Celta and the host was thankful to goalkeeper Tono as he made a number of fine saves after the break, most notably to deny
Four second-half goals - three in the last eight minutes - saw Osasuna wrap up its first victory of the season as it despatched a poor Levante side.
In the late game, Atletico Madrid leapfrogged Malaga and returned to second place as Raul Garcia decided a 1-0 victory over rock-bottom Espanyol.
The former Osasuna midfielder headed home a superb cross from the right by Juanfran but, despite claiming its fifth straight league win, it was not wholly impressive and was stretched by an Espanyol side which remains anchored to the bottom of La Liga with just one point.
Atletico, meanwhile, sits just two points shy of Barcelona.
Valladolid put a three-game losing streak behind it in emphatic fashion by thrashing Rayo Vallecano 6-1 thanks to braces from Manucho and Oscar Gonzalez.
Alejandro Dominguez had fired Rayo into the lead after just five minutes, but that was as good it would get for the visitor as two goals in three minutes from Alberto Bueno and Manucho put Valladolid in front.
Oscar then got his first with a lovely chip over Ruben Martinez before Omar Ramos teed up Antonio Rukavina to fire in a fourth before half-time.
The chances continued to flow for the host in the second half and, after Oscar had stroked home the fifth on 55 minutes, Manucho capped a wonderful individual display by smashing in his second five minutes from time.
Real Sociedad coach Philippe Montanier is to leave the Primera Division side at the end of the season after turning down a contract extension, the Basque club has confirmed.