Just look at 3/4 of your defense. It's not on par, but even lower than his attackers.

You pay to play and from what i see you pay a good bunch, i bet you were set on offensive, both flanks, red arrows on your wingers. If i might imagine, defensive style, counter on, blue arrows on the sides, red on the middle for him. It isn't that abnormal that his attackers owned your defenders, expecially on counters. SPending doesn't mean you can win 100% alwais playing offensively "coz you are >9000".
I actually won over 5-0 results the time that i switched from offensive to defensive taking back from full pitch to own half aftr 4-5 goals. Tecnically, they push more to recover the wide gap, and you got a desert when you counter. That way i win 8,9, sometimes 10-0. On Defensive setup. With those poor defenders, you shoulda have reinforced the DM zone, and prolly you woulda have won easily. As for your friend, he probably had better defenders then you who sufficed to stop his underated players.

Ofc this is just an hypotesis, if you would post your orders and arrows i could say better.