Can't see the last battle report. Beacon tower effects scouting too, but i assume it's level 9-10. Reinforcements could have been on their way already, since he had only 1000 AT's - he might have been under attack before and reinforced hours ago. Might have just gotten the luck that they arrived just before your attack had hit (happened to me).

Other then this i can't think of anything before seeing the report.