A youthful Blues side started confidently and opened the scoring through 17-year-old Kazakh wonderkid Dastan Satpayev.
The Blues were quickly pegged back, though, before the hosts took a shock lead just past the half-hour mark.
The impressive Dario Essugo drew Chelsea level before half-time, but it was Western Sydney Wanderers who would strike again after the break to take the lead once more.
Shortly after, Xabi Alonso rang the changes and saw an immediate uplift in his side’s performance as Jamie Gittens netted to continue his fine start to pre-season.
More defensive lapses would once again see Chelsea concede, though, as Western Sydney Wanderers regained the lead for the third time in the game.
Eventually Chelsea’s quality shone through as Joao Pedro, who had earlier assisted Gittens, scored a nine-minute hat-trick to continue Alonso’s perfect start to pre-season.
Joao Pedro ready to be Alonso’s leading man
Following a superb debut campaign in west London, he looks ready to put the disappointment of missing out on Brazil’s World Cup squad behind him.
Introduced among a whole host of second-half changes, the 24-year-old did not find it difficult to stand out as he took the game away from a stubborn Western Sydney Wanderers side with a performance that barely saw him step out of second gear.
Brought on to capitalise on tiring legs, Joao Pedro made an immediate impact as he bustled his way to the byline before cutting the ball back for Gittens to tap home.
Hat-trick hero: Joao Pedro underlined his importance to Chelsea with a quick-fire treble
AFP/Getty
A fine piece of industry was followed by a moment of quality as he picked his corner with ease to draw Chelsea level moments after Western Sydney Wanderers had struck to make it 4-3.
Joao Pedro was not done there, though, as he raced on to Cole Palmer’s through ball to give Chelsea the lead before completing his hat-trick by firing in from close range after a corner.
It is still unclear who will provide back-up to Joao Pedro this season, with the futures of Liam Delap, Nicolas Jackson and Marc Guiu all in doubt.
Alonso will hope that by bringing in Joao Pedro’s former mentor at Brighton, Danny Welbeck, he can eke even more goals out of the £60million man.
Defensive frailties show no signs of improvement
Chelsea have always been capable of entertaining under the BlueCo ownership. Palmer’s magnetic creativity has at times made that inevitable.
It is in defence, though, where Chelsea’s ambitions have stumbled. Poor recruitment and injuries have led to an unsettled backline that has struggled for consistency and confidence over the years.
Alonso knows that without a defence he can rely on, his grand plans for Chelsea may never get off the ground, and he will have been reminded of that against Western Sydney Wanderers.
A young and inexperienced defence, marshalled by understudy centre-back Tosin Adarabioyo, struggled with difficult playing conditions and a brave performance from the hosts.
Concern: Tosin Adarabioyo led a struggling Chelsea defence in Sydney
AFP/Getty
This was no easy introduction to pre-season, which Alonso will be quietly pleased about, and it exposed the many flaws that still exist in Chelsea’s defence.
Undone from a corner, lucky not to be punished for their lackadaisical passing, and ultimately too tentative in response to an aggressive, transitional performance from Western Sydney Wanderers, there will be plenty for Alonso to ponder.
The fact Alonso is unlikely to know for certain who his centre-back options are before the season starts makes his task all the more difficult.
Youngsters take their chance in trying conditions
The condition of the pitch at Sydney’s Accor Stadium will have frustrated Alonso, not only due to the risk of injury but also the difficulties it presented his side with in trying to play their passing game.
The bobbly surface made it tricky for Chelsea to play through the lines smoothly, but the Blues adapted well, with teenage midfielders Reggie Walsh and Reggie Watson handling the ball well under pressure.
Strong impression: Reggie Walsh shone in the heart of Chelsea’s midfield
Getty
The academy pair are highly regarded internally and made a good impression as Chelsea put together a number of flowing, attacking moves that will have impressed Alonso.
Watson was the standout performer for Chelsea in the first half, and while guilty at times of overplaying, his confidence in possession allowed Chelsea to go from back to front in an instant.
Walsh was also heavily involved, combining neat touches and close control to play out of pressure and draw fouls.
Pre-season provides an opportunity for academy players to make their mark, and Walsh and Watson took their chance with aplomb.
