CHERRY RED RECORDS STADIUM, LONDON—Jose Mourinho is famed for many things as a coach.
Behind the headlines, soundbites and suave dress sense is a manager determined to succeed and intent on excellence.
One of his many techniques is to use his training drills as match scenarios, instructing his players to play out situations in games when they need to get a win or hold out for a draw with 10 men.
The intention is that, come the real thing, they will be drilled enough and confident enough to successfully perform the task against any opponent.
He may not have planned for it, but Mourinho got just that against AFC Wimbledon on Saturday.
Chelsea trailed within 40 seconds after Alan Bennett headed home a corner and things got worse just before the break when Matt Tubbs was barged to the ground by Kurt Zouma for a penalty.
Had it been a competitive fixture, as the last man, there's no doubt Zouma would have received his marching orders. Instead, he remained on the pitch to see Tubbs confidently convert from 12 yards, doubling the lead.
Chelsea eventually clawed their way back into the game, with Mohamed Salah and a John Terry brace giving them a 3-2 victory over their League Two opponents to save their blushes.
Indeed, one journalist in the press box at the Cherry Red Records Stadium was busy adding up the total value of Chelsea's line-up in the hope minnows Wimbledon would get one over the money bags Premier League side.
It wasn't to be. Chelsea eventually got the job done, but not quite in the fashion Mourinho would have liked.
The whole point of pre-season is to get players fit, and systems refined, in place and understood for the new season. By that measure, there were plenty of positives to take from the Wimbledon victory, notably the character and determination Chelsea displayed in not shying away from the hole they had dug themselves.
The game even allowed for the manager to test the impact of putting Branislav Ivanovic in attack, acting as a battering ram to get Chelsea back into the game.
It proved a lesson learned ahead of 2014/15 and a tactic we may see again if the Blues find themselves feeling desperate.
Mourinho will lament the naivety of his young players, however.
From thrashing Wycombe Wanderers 5-0 midweek, the Blues lacked the urgency and creativity to threaten Wimbledon in the first half.
They dominated possession, but did very little with it, starving Patrick Bamford of any service. Come half time, the No. 9 cut a frustrated figure.
It took the leadership of Terry to inject the impetus Chelsea needed, with fellow half-time substitutes Izzy Brown and Lewis Baker causing the damage their teammates had earlier struggled to inflict.
The pair, along with Jay Dasilva, really impressed, but without their more experienced teammates around them, Chelsea seemed to struggle in carving out openings to make their superior ability count.
That's the problem with youth. A player can be vastly talented, yet until he learns how and when to apply himself, it can prove more a hindrance than anything.
Whether it was over confidence, cockiness or just inexperience, Chelsea were often guilty of over playing, looking for that extra pass to play their way through the opposition defence.
At times they retained possession too long, picked out the wrong teammate or lost composure, making wayward passes that Wimbledon capitalized on. In fact, Wimbledon's penalty came from a simple long ball after Chelsea had lost possession in their half.
Mourinho has no choice but to play his youngsters right now. With so many World Cups stars yet to report back to training, he's beginning to learn a lot about the next generation and which players may be able to force their way into the first-team squad.
It's an exciting time to see these new faces given a chance, but, either way, for all their talent, the Chelsea boss knows there is a long way to go before the Blues' kids are ready for Premier League action.
Garry Hayes is Bleacher Report's lead Chelsea correspondent. Follow him on Twitter @garryhayes