Talk:Alliance/@comment-14.169.62.132-20150311114441/@comment-25151790-20150311194835

AUB assists happen when other members of your alliance have a winning streak. You can be assisted by up to three members. If there are more than three members with winning streaks, the three are randomly chosen from the members with winning streaks. The card chosen for the assist is the card in their attack units with the highest Attack stat.

The case where the max Attack GUR was able to defeat an HSR might be different for each battle. It could be the case that when your alliance mate was attacking, he used a skill to increase his damage or the HSR in the defending team did not have max Defense. The defending team you faced might have had their HSR's Defense stats maxed out.