5:1 victory at the end!
The difference in quality was not that big - he had two of his top players banned for one cup match so it brought my team disadvantage to about 6%.
I started with 4-1-2-2-1 V, defensive style and counter attacks plus team bonus on defense. He scored first so I changed to normal style, short passing and team bonus on attack in the second half and.... 5 pieces!
Second leg won't be that easy but 4 goals lead and home ground are quite a good start even against much stronger opposition.
Plus the team bonuses work very good - with both managers watching the match and full stadium (meaning 5% for him) I had 58:42 possession. I had more players in the midfield but his quality was higher so the difference should have come by the 10% team possession bonus from training.