Is this the same team that struggled against Getafe earlier this season and spent nearly three months trying to find top form?
For really the first time this season, Real Madrid look like champions.
Sure, Athletic Bilbao are a bottom-half team who never had a great chance of upsetting even an out-of-form Madrid side, but they are still a tough opponent.
Los Leones have a lot of great talents and a manager who can always cause problems for big teams.
Los Merengues proved once again to be lion tamers as they stifled Bilbao and never gave them a real chance to even get in this game.
Karim Benzema scored a glorious goal and probably would have had a hat trick if not for some great shot-stopping in the Basque goal.
After seeing the defending Spanish champions dismantle Athletic Club, let's take a look at some things we learned.
Now this is how we expect champions to play.
Real Madrid have now won five straight Primera Division matches, but this is the first time that they truly looked like the record-setting team of last season.
From the very first whistle, Los Merengues looked unstoppable.
It took Cristiano Ronaldo just four minutes to take his team's first shot and they didn't let up for the rest of the match.
An own goal allowed Madrid to open the scoring after barely 10 minutes while the defense was almost impenetrable.
This match was dominated by the hosts in almost every facet of the game.
Madrid had nearly three times as many shots—29 to 11—putting 18 of those on goal compared to one for Bilbao, earned nine corners and won nearly 70 percent of the aerial battles.
The Basques actually won the possession battle, but were never allowed much time on the ball in threatening areas.
The hunger is back
Perhaps most impressive part of this win was the work Madrid put in from start to finish.
Jose Mourinho's men were continuously pressing Bilbao off the ball, relentlessly attacked goal, and were spectacular at the back.
This was also the best that Madrid's defense has looked all season.
It may have been against a far inferior opponent and Madrid need to keep this form up to really have a chance at retaining the title, but if Los Merengues can play at this level every week going forward, it will only be a matter of time before they start chipping away at Barcelona's lead.
That brief bit of hope Bilbao fans had coming into this match now looks foolish after watching their team get played off the pitch in Madrid.
After a pair of wins, Los Leones managed to pull themselves out of the relegation battle and finally looking like a contender for a spot in the top 6.
The reigning champions destroyed that facade with a barrage of goals that showed just how poor Bilbao is.
The defending was just awful as the entire back line looked slow and got abused all night.
They allowed nearly 30 shots to be taken with the majority of them coming inside or near the box. 5-1 is an embarrassing scoreline, but it really could have been much worse.
It wasn't just the back line, though. There was no direction or leadership in midfield, no creativity leading to goal chances and absolutely no finishing.
With only one shot on goal in 90 minutes, not even starting Fernando Llorente would have made much difference.
The bigger picture
Depending on how the remaining league matches go, Athletic Club could find themselves as low as 15th place, just four points above the drop zone.
In Europe, the Basques are on the verge of dropping out of the Europa League group stages after a string of poor performances.
They're also in a tough spot in the Copa del Rey as a goalless match at lowly Eibar sees them one goal away from being bounced in the first round.
Looking at the overall strength of this team, the lingering internal issues, the inconsistent play and the very poor defense, we have to wonder what the expectations are for Los Leones this season.
Athletic Bilbao should stay in the first division and keep their great record alive, but the chances of them playing in Europe again next season look very small at this point.
The only Basque player who seemed to show up in Madrid ready to play was Bilbao's great keeper.
Gorka Iraizoz surely did not leave the Santiago Bernabéu with much pride after letting five goals slip in, but perhaps he should have.
The 31-year-old really had a great game against Madrid. Iraizoz made a total 18 saves on the night, including five world-class stops that kept his team from a record defeat.
The shot-stopper was on his game for most of the match and four of the goals would have been hard for anyone to stop.
The one goal that he probably should have done better with was Khedira's, but considering how hard he worked from the fourth minute, he is allowed one mistake.
Iraizoz finished the match with 66 touches. That's more than any Real Madrid player had besides Luka Modrić. Don't forget that we're talking about a keeper here.
Cristiano Ronaldo failed to score for the third time in four games, but unlike those previous matches, he played a great, complete match against Bilbao.
The Portuguese international was involved in countless attacks from the start of the game and continued to cause problems for the Basque defense.
He made some excellent passes—including the one that freed Benzema before the Frenchman set up Ozil for his goal—and continuously got in position to shoot.
His shooting was rather poor as he never really troubled Iraizoz in goal, but he was still constantly getting in position and finished with seven shots on goal.
Much better than stats suggest
Lately Ronaldo has been wasteful and even a bit selfish by shooting when his teammates were in better position to score, but that was certainly not the case this time.
Not only was CR7 far from selfish, his shooting was on target most of the time. He just didn't send many tough shots on goal.
He finished the match without any great statistic to his name, but Ronaldo had a superb match nonetheless.
In truth, Mourinho probably should have taken Ronaldo off around the hour mark with the game decided and a huge Champions League game coming up Wednesday.
This season Bilbao has been a team in turmoil. Their struggles on the pitch only tell half of the season.
We've already learned their coach resigned only to decide he wants to stay, their best player was sold to Bayern Munich and their second-best player was benched due to a managerial dispute and a spoken desire to leave the club.
While the entire team is suffering, few players have been more affected by this instability than Iker Munian.
Fall from grace
Last season the Basque teenager was one of the hottest commodities in football.
After a great season that included world-class performances against Barcelona and Manchester United, the greatest club in Europe were fighting for just a chance to sign the young star.
This season the 19-year-old looks a shadow of his former self and is nowhere near the great player we've come to enjoy over the last two seasons.
Munian's poor form started with his disappointing showing at the Euros—where his petulance and immaturity cost him at least his short-term future with the senior squad—and has now continued well into November.
Failure in Madrid
Against Madrid, the teenager was taken off at halftime after sustaining a thigh injury, but the team really didn't miss him that much.
Unlike the creative, hard-working star we saw being born last season, Muniain really struggled to control the game in a more central role in this match.
When he was subbed off, Muniain had the second-worst pass completion percentage on the team—77 percent.
He didn't manage a single shot on goal and struggle to create much space or any scoring opportunities despite being in the middle of most transitional plays.
The internal issues at Bilbao are certainly affecting Muniain's and there is a chance that this season becomes a major set back for the Basque prodigy.
This Wednesday we will see the defending champions of Spain and England clash for the second time this season.
If we look at recent results at face value, it would appear that Manchester City and Real Madrid are in similar form when they square off.
Both teams managed 2-2 draws in their last Champions League match, won their next league games over tough opponents and then scored five goals this weekend.
Of course, the final scoreline does not tell the whole story.
While both teams will enter Wednesday's match feeling confident about putting up five goals over the weekend, the Spaniards will have a slight edge.
While Athletic Bilbao are a poor team this season, they are still better than relegation-battling Aston Villa.
Also, this is not the first big win for Los Merengues recently. They've scored 16 goals in their last four league matches while allowing just two goals.
In that same span, Man City have allowed just one goal, but scored only eight while also drawing against West Ham.
All is not equal in Europe
While both teams played to a 2-2 draw in their last group stage match, Madrid had to come back on one of the tournament favorites while Man City were basically outplayed by an inferior opponent.
Even beyond the latest match, though, the English champs have been very poor in Europe.
They have not been the better team in a single match and were lucky to earn a point against Borussia Dortmund.
Madrid were also outplayed by the reigning champions of Germany, but still managed a point and dominated the same Ajax team that twice proved better than Man City.
Perhaps most importantly, Madrid have the pedigree and experience to overcome these dropped points while their Wednesday opponents do not.
Concern for the English
Both teams may be in good form right now, but Real Madrid are coming off perhaps their best win of the season.
Los Merengues finally look like the team that broke so many records last season and will be feeling much more confident than Man City who know they have to beat the Spaniards to have a great shot of making it out of the group stages.
Even with Mourinho failing to rest more stars this weekend, the added pressure and great form from Madrid could spell trouble for the English come Wednesday.