Arsenal's Community Shield triumph was no routine friendly win. Chelsea are understrength and underdone. We look at six big issues to come out of the Wembley clash.
MOURINHO CAN'T SPIN IT - CHELSEA ARE WOUNDED
Maybe it was the rivalry of the managers, but this Community Shield was no friendly. The tackles were full-blooded, the passing was snappy and the work-rate from both sets of players on a level of any Premier League game.
Santi Cazorla was hammered several times by Chelsea defenders. Cesc Fabregas was left in a heap by Gunners rival Francis Coquelin. And Mesut Ozil took one to the midriff from Chelsea midfielder Ramires. There was even an all-in brawl sparked by Radamel Falcao. This result mattered.
Jose Mourinho went into the game mocking Arsene Wenger's record against him. Thirteen failures and counting - until yesterday. Mourinho's now claiming he was never bothered . Do us favour, Jose!
Wenger's broke the drought. His one major signing, Petr Cech, completes his competitive debut with a cleansheet. And there's a first trophy for the season - and first victory over his Blues nemesis.
For Mourinho, it's more headaches. Where will the goals come from? Falcao didn't look up to it. Remy struggled. And if Cesar Azpilicueta breaks down, what happens at left-back?
Sure, Diego Costa was missing for Chelsea. But so was Alexis Sanchez for Arsenal.
We've all had it drummed into us now: no-one can afford a slow start to the season. Every point counts. Mourinho can spin it however he likes. The champions are wounded. This is not the Chelsea of August 2014.
PETR CECH WILL MAKE DIFFERENCE
Arsene Wenger is right when saying Petr Cech had a psychological effect on the game. But it wasn't Chelsea who were influenced, instead Cech's calm demeanour gave the Gunners' back four a sense of assurance as the Blues chased down Alex Oxlade-Chamberlain's goal.
Cech will be delighted with his clean sheet on debut. As will Wenger. He looked part of the Gunners' furniture. Indeed, he looked more a long time Gunners keeper than either Wojciech Szczesny or David Ospina during the entire last season. Even an error was dealt with a calm assurance. A flap in the second-half didn't go to plan, but Cech cleaned up that initial effort with a thumping punch clear - while steaming into the back of his former captain, John Terry. The jitters and nerves of Szczesny inside a crowded penalty area were gone. This is what Cech will bring to Arsenal this season.
And he was tested. It was no walk in the park. He was stretched at times, but never fell short.
However, Wenger's wrong to attempt a little dig at Chelsea about Cech's sale. For as assuring as he was for the Gunners' defence, at the other end, Thibaut Courtois showed why there was no alternative for Cech but to leave Stamford Bridge this summer. Oxlade-Chamberlain's goal was a screamer. But the Belgian, with Chelsea wide open as they chased the game, twice saved superbly in one-on-one situations to give his team every chance of getting an equaliser.
As much as he'll be frustrated seeing Cech on Arsenal's team sheet, Jose Mourinho knows he has the better keeper.
A BREAKOUT YEAR FOR WILLIAN?
Can this be the breakout year for Willian? The Brazilian was as good as anything on the Wembley pitch yesterday. He covered every blade of grass and certainly was consistently Chelsea's most inventive player - outshining Cesc Fabregas and Eden Hazard.
Perhaps he's further along in preseason than the rest. But it's difficult to recall a better, more consistent performance in a Blues shirt from the midfielder.
Jose Mourinho put his attacking midfielders on notice last week, suggesting he needed someone a level higher to really make the leap into Europe's elite. But if yesterday was no one-off, then Mourinho already has that world-beater under his nose.
COQUELIN JUSTIFIES WENGER FAITH
More is always going to be demanded more from Francis Coquelin. Maybe it's because there's no big price-tag. Perhaps it's just the manner of his recall from his problems at Charlton Athletic. But the Frenchman is always going to have go that extra mile to keep the critics silent. Think Nicky Butt and Manchester United.
He was at it again yesterday. He had Cesc Fabregas and Eden Hazard in his pocket for much of the game. But it wasn't just his defensive game that caught the eye. Coquelin displayed an impressive range of passing when in possession, clipping the ball through Chelsea's defensive lines for the likes of Theo Walcott and Alex Oxlade-Chamberlain to run onto.
With Mathieu Flamini and Mikel Arteta now acting as experienced backups, perhaps Arsene Wenger is right to stand by Coquelin and ignore the calls to make a defensive midfield signing.
GIROUD SHOULDN'T BE MESSED AROUND
Olivier Giroud is Arsenal's No1 striker. Not Theo Walcott. The Frenchman deserves the status and should be first-choice for Arsene Wenger. Arsenal are a better team with Giroud leading the line - it's a simple fact.
Though Arsenal had gone 1-0 ahead with Giroud watching from the bench, they never looked as dangerous as when the centre-forward finally entered the fray.
Yes, his cameo was scattergun. But the important thing was that chances were being created. He had Chelsea on the backfoot, either through his presence inside the penalty area, or with his knockdowns for teammates to run onto.
Giroud complained late, last season about the lack of recognition he felt he'd received. And he has a point. Wenger should be shopping for a striker to work with Giroud, not as a replacement. Nor should he be selecting Walcott ahead of the Frenchman.
CHELSEA SUPPORT CAST NOT UP TO IT
The support cast just don't look up to it. With Diego Costa rested, Loic Remy was hooked at halftime and Radamel Falcao looked a yard short in pace and fitness. Indeed, Remy can feel aggrieved as the Frenchman was the better performer.
It must concern Jose Mourinho that so much of their goalscoring power will depend on Diego Costa this season. But it doesn't begin and end with the strikers.
Mourinho threw on Kurt Zouma late into the game - at left-back. And Zouma's no left-back. Those declaring the champions as favourites for this season's title haven't taken a look at the current squad compared to 12 months ago. It's weaker. Didier Drogba, Mark Schwarzer, Petr Cech, Fernando Torres, Filipe Luis and Andre Schurrle have all gone. They may not have been frontliners, but they could make a difference.
The first XI is outstanding. But one or two major injuries and Chelsea will be scrambling this season.