Paul Heyman opened the limousine door for Roman Reigns halfway through the show, only to be greeted by his former client Brock Lesnar.
The big story coming out of SmackDown was Brock Lesnar appearing to attack Roman Reigns, something Lesnar promised he would do.
The show had several highlights, starting with the first bout of the main card, a thrilling Hell in a Cell match between Edge and Rollins.
Most notable among those who switched brands was Charlotte Flair, who was drafted to SmackDown despite being the current Raw women's champion.
Despite a spirited effort from "The Demon" Finn Balor, a higher power seemed to allow Roman Reigns to successfully retain his championship.
The show took a big swing on Monday, bringing universal champion Roman Reigns over from SmackDown for what turned out to be two matches.
Reigns and The Usos will have to take on Big E and New Day teammates Kofi Kingston and Xavier Woods in a six-man tag match on Raw.
Roman Reigns defended his Universal Championship title against a charged-up Finn Balor.
Finn Balor said he was screwed out of his opportunity at SummerSlam by Cena and he wouldn't sit by while Edge and Lesnar are lurking around.
SummerSlam 2021 was full of surprises. The returns of Becky Lynch and Brock Lesnar. Lesnar faced off Roman Reigns after his victory.