Real Madrid got their La Liga campaign off to a winning start as they beat newly-promoted Cordoba 2-0 at home, but champions Atletico Madrid were held 0-0 away to Rayo Vallecano on Monday.
Without the Manchester United bound Angel di Maria, Real were also far from convincing at the Bernabeu but got the three points thanks to Karim Benzema's first-half header and a characteristic thumping finish into the bottom corner from Cristiano Ronaldo in stoppage time.
However, there was no such joy for Atletico as with coach Diego Simeone watching on from the stands they played out a bore draw with Rayo.
Simeone had been handed an eight-match touchline ban earlier in the day for his conduct towards the officials in the second leg of Atletico's Super Cup victory over Real on Friday and his side suffered a hangover from that match in a lacklustre performance.
Mario Mandzukic had been the match winner against Real, but the Croatian striker had an evening to forget at Vallecas as he wasted Atletico's best two openings towards the end of the first-half as he fired into the side-netting from Cristian Ansaldi's low cross and then placed a shot too close to Rayo keeper Cristian Alvarez from the edge of the area.
Rayo had by far the better of the second-half, but despite their failings going forward, Atletico remained solid at the back.
Manucho had the best chance to win the game as he dove to meet Javier Aquino's cross, but his header was turned away by Atletico keeper Miguel Angel Moya.
Real boss Carlo Ancelotti also believed his side's below par performance was down to their exertions against Atletico.
"There was a bit of tiredness because since the 12th we have played every three days and it is not an easy time of the season to do so," Ancelotti said.
"We suffered a little bit, but we controlled the game. We tried to mix possession with playing a bit more direct and I think we were well-balanced."
Cordoba were playing in their first top flight game for 43 years and nearly had a dream start against Real's galacticos when Mike Havenaar pulled his shor just wide from the edge of the area.
The European champions slowly began to impose themselves on the visitors as the first-half wore on and Juan Carlos had to be alert to parry powerful efforts from Ronaldo and Kroos.
Madrid did go in front on the half hour mark as Benzema ended his four-month goal drought at club level with a thumping header to power Kroos' corner in off the post.
However, Cordoba were nearly level from a corner of their own just before half-time when Havenaar got between Casillas and the Real defence but saw his header fly just off target.
Cordoba appeared to take heart from that opportunity, though, as they were the better team after the break against disjointed Madrid.
Casillas was forced into his first serious save as he pounced on Matos' shot after an error from Alvaro Arbeloa.
James Rodriguez struggled to recreate his stellar World Cup form on hs home league debut after a 75 million euro ($99 million, 60 million pounds) move from Monaco, but the Colombian did nearly make the game safe for Los Blancos with a fierce strike that Carlos did exceptionally well to parry to safety.
Madrid were served a warning 20 minutes from time when Casillas could only parry Fidel's effort into Xisco's path, but the former Newcastle United forward's finish was rightly ruled out for offside.
And despite failing to shine, Real did eventually ensure they started with a win as Ronaldo picked up the ball midway inside the Cordoba half and strode forward before unleashing a fine shot low past Carlos.