The most energetic Summer Jam moments came in the first half of the show. If you were fashionably late, you missed out. Alicia Keys was onstage at 7:05 p.m., just 35 minutes after the official showtime and third in the lineup behind Ray J and The-Dream.

Keys started off with the reggae-tinged “Ghetto Story” and had the whole stadium going “Rah! Rah! Rah!” “Teenage Love Affair” followed, and then she started paying homage to Mary J. Blige, singing “Be Happy” a cappella. The beat for the remix to “Be Happy” kicked in, and out came Brooklyn’s Maino. His current street thumper “Hi Hater” shamelessly jacks the beat from the Queen of R&B soul’s classic.

Thousands waved their arms side to side with open palms. Imaginary foes were greeted with sarcastic adoration, “Hi, hata! Hi, hata. You see me. Hi, hata.” Ms. Keys then pulled out her trump card with one of her favorite groups, the Wu-Tang Clan. First, Raekwon the Chef came out for “Incarcerated Scarfaces.” Method Man and Ghostface Killah appeared a couple of minutes later and helped Rae on “Ice Cream.” Method Man jumped in the crowd during “Method Man.” Keys’ set was showered with applause as she set the standard for the night early on.