3-4-3 can not be countered with 4-3-2W-1 as 1 lone st (even with supports from 2 wingers) is not enough to put pressures on the 3 dcs line. A motivated formation btwn 4-4-2 Classic and Hexagon with 4-3-1 winger and 2 STs will be ideal to counter 3-4-3. (Ml,mc,Mc, Amr or vice verse), focus mixed, own half, mixed passing, red arrows on 2 Sts so the 3 dcs will play under hard pressure and the lone winger will be the key-player of the match with cut inside situation and long shots. Good luck