Espanyol continue to be the only team in the Spanish top-flight without a win this term, having taken just two draws from their opening eight league fixtures.
Celta cruised to victory, though Pierre Wome did not help the hosts' cause by being dismissed after 34 minutes.
By that stage Peter Luccin had already put Celta ahead, and three second-half strikes underlined the Galicians' dominance while goalkeeper Erwin Lemmens also saw red Espanyol.
Savo Milosevic, Alexander Mostovoi and Jandro all found the net to heap further pressure on Espanyol's under-fire coach Javier Clemente.
Real Betis climbed into fifth spot after a narrow 3-2 home success over struggling Albacete.
Mikel stunned the Ruiz de Lopera stadium after just 11 minutes when he fired the visitors ahead, but two goals in the space of four minutes before half time turned the game on its head.
Former Real Madrid hit-man Tote grabbed his second goal in two games on 41 minutes and Fernando's penalty then ensured Betis went in at the break ahead.
Capi added a third for 'los verdiblancos' on 50 minutes, and though Parri reduced the deficit with 25 minutes remaining, Albacete could not find an equaliser.
Real Sociedad jumped five places to sixth following a 1-0 victory over Osasuna, Darko Kovacevic was the hero for the Basque outfit netting the all-important goal with just 14 minutes remaining.
Barcelona climbed back up into the upper echelons of the table with a convincing 3-1 win at Mallorca.
Javier Saviola got the ball rolling for Frank Rijkaard's men after nine minutes, and Brazilian Ronaldinho continued his excellent recent form with a stunning second a quarter of an hour later.
Philip Cocu wrapped up the points for the visitors on 50 minutes with a third, though there was a flurry of action in the dying minutes as Fernando Correa grabbed a late consolation for the Islanders before Barca's Gabri got his marching orders for two bookable offences.
Atletico Madrid made it three wins on the trot in all competitions after a 3-1 success at Murcia.
Striker Fernando Torres was the hero for the capital club notching a brace; his first came on 13 minutes from the penalty spot and Greek hit-man Demis Nikolaidis then opened his Atletico account eight minutes before the break recording his first La Liga goal for the club since his summer move from AEK Athens.
Murcia briefly threatened to get back into the game when substitute David Karanka reduced the arrears 20 minutes from time, but Torres' second on 83 minutes killed the contest.
Villarreal and Sevilla shared the points after a six goal thriller at El Estadio Madrigal.
The visitors lead on three separate occasions, but each time were pegged back by the Yellow Submarines.
Francisco Casquero (3), Jose Antonio Reyes (penalty, 23) and Carlos Dominguez (83) were on target for Sevilla, while a Sonny Anderson brace (11,68) and a last-gasp Rodolfo Arruabarrena were enough to ensure homours ultimately ended even.
Real Valladolid eased away from the bottom end of the table with a comfortable 2-0 win over high-flying Athletic Bilbao, goals in each half from Francisco Sousa and Ariz Makukula hamded the points to Fernando Vasquez's troops.
Match summaries:
Espanyol 0-4 Celta Vigo
Mallorca 1-3 Barcelona
Murcia 1-3 Atletico Madrid
Real Betis 3-2 Albacete
Real Sociedad 1-0 Osasuna
Valladolid 2-0 Athletic Bilbao
Villarreal 3-3 Sevilla
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