to kill this,first take out sakura cos while she is on the field u are not killing anything(same lv) so after u have taken out sakura water main is the only heal so take her out(if using heal)if not take her out to cut or the summon combo damage and connecting now after u have taken out main and sakura it is a race of doing damage before 10 rounds are up.
u can't do anything else short of overpowering this team as this team is made with lower and same lv people in mind so unless u are 9-10 lvs higher u have to wing it with common sense in mind.