User blog comment:B214/General Discussion/@comment-86.149.139.182-20161003170703/@comment-9595671-20161003230007

In fact I think the boost that Issei gave Rias during the fight with Kokabiel is a good example it's like they had the Boosted Gear. I doubt Issei boosted enough to made Rias have power near that of her big brother in that short span of time.