Diego Costa's imminent exit and Eden Hazard's injury matter precious little as Arsene Wenger's men find it one too many games: FIVE THINGS WE LEARNED as Chelsea defeat Arsenal

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Chelsea were in a ruthless mood as they met Arsenal for the first time since last season's FA Cup final and put the Gunners to the sword with a 3-0 victory in Beijing

Willian opened the scoring early on before Michy Batshuayi bagged himself a brace to seal a comfortable victory for the Blues.

Here, Sportsmail's Matt Barlow brings us five things he learned from Beijing. 

Michy Batshuayi sealed Chelsea's 3-0 victory over Arsenal with a brilliant brace 

Costa's off, Hazard's injury? Nothing to worry about... 

For all the concern about Diego Costa's imminent exit, Eden Hazard's injury and a lack of depth, the Chelsea team still possesses terrific balance and power and were thoroughly prepared for what was their first public outing of pre-season. 

They fired eight past Fulham behind closed doors last week and, in Beijing, they dominated Arsenal who were playing their fourth tour game and will probably plead some sort of fatigue. 

Antonio Conte has clearly got through some important preparation during the 10 days they have been back in training. The champions looked fresh and slick.

One game too many for the Gunners 

Arsenal's ambitious tour of Australia and China proved to involve a game too many. Arsene Wenger was diplomatic when asked in Shanghai if this was the best way to prepare for a long season, ending for many of his players with a World Cup finals. 

The Gunners played twice in Australia and trained hard through double-sessions in the sweltering heat of Shanghai. 

A stomach bug laid several players low and somehow they still managed to beat Bayern Munich on penalties. Here they looked distinctly weary and ready for home.

It proved to be one too many games for Arsenal as they couldn't cope with Chelsea 

Fabregas is the great survivor 

Cesc Fabregas is the great survivor of the Conte era at Chelsea. It is more than a year since the Italian manager arrived at Stamford Bridge and decided Fabregas was surplus to requirements. 

But the Spain international refused to budge, improved his fitness and convinced Conte he can play a role. This summer, Costa and Nemanja Matic have been shown the door by ruthless Conte but Fabregas remains. 

As last season, he will provide extra craft when required in certain games. His passing is as sublime as ever judging by this performance. And he was reassuringly booed by the Arsenal fans in the Chinese capital.

Cesc Fabregas has proved he is the great survivor having watched others be shown the exit

Elneny to central defence 

Mohamed Elneny may be the latest convert to life as a central defender amid this fashion for three at the back. Nacho Monreal has excelled on the left of the trio since Wenger made the tactical switch at the end of last season. 

Elneny, well down the pecking order in central midfield where he likes to play, has also shown signs he might be able to fill in at the back at least against teams who don't launch the ball aerially onto the central defenders. 

Young midfielder Ainsley Maitland-Niles, for all his ability and promise, has not made such a smooth transition to life at the back making mistakes which gifted two chances to Willian, who scored from neither.

Mohamed Elneny may be the latest convert to life as a central defender at Arsenal

Batshuayi has a point to prove 

Michy Batshuayi is brimming with confidence and has a taste for goals since he came off the bench to win Chelsea the title with a goal at West Bromwich Albion last season.

The Belgian scored twice in the eight-goal romp against Fulham on Saturday and twice more against Arsenal and saw another goal was disallowed for offside. Chelsea's frontline have seized the opportunities offered by Hazard's injury and Costa's exile. 

Willian scored a hat-trick against Fulham and was on target again in Beijing. An injury to Pedro, flattened in a collision with David Ospina, will be more of a concern for Conte. Batshuayi however will be a fine acquisition for a Premier League team in need of goals if Chelsea decide they can do without him.