Jennifer Lopez and Enrique Iglesias at Prudential Center Jennifer Lopez at the Prudential Center in Newark. NEWARK - Four songs into her performance at the Prudential Center here on Friday, Jennifer Lopez, standing in rhinestone gym clothes, absorbed some applause. And she confirmed what she had announced a week earlier: that she was leaving "American Idol" after two seasons as a judge. "I just want to take this moment to thank all of you for all your support and your love during my time on "Idol," " she said. It was an amazing experience for me, and I'm going to miss it very, very much, but at the end of the day this is what I do. This is where I belong, right here with all of you. Gracious, in line with industry standards, and dull. Likewise most of her show, the first in the United States of her joint-headlining North American tour with Enrique Iglesias. This means that both sets run about equal length and that there are two confetti-cannon moments. Ms. Lopez's entrance was ludicrous but funny: eight male dancers in top hats and tails, with walking sticks, singing about "the most beautiful girl of your dreams," while a cherry picker lowered her, in fur and feathers, from a great height. From then on it was a trudge, even with costume changes and dancing. Ms. Lopez, now 42, showed us what she wanted to show us about her work ethic, her values and her relevance: as a beauty, a mother, a Latina, a romantic, a former Bronx girl and early-"90s hip-hop dancer, and as a pop singer who now makes club tracks, and like so many others, has Lil Wayne and Pitbull rap on them. Her meager voice is not necessarily, or always, the problem; perhaps it's more that she's incurious about making the best of a weakness. She got inside her stage conceits - a boxing ring for the new dance track "Goin" In," a nightclub for the ersatz salsa in "Let's Get Loud" and "Papi" - but not her songs themselves. She rarely filled up her own music, except perhaps for "Until It Beats No More," a soft-rock ballad about redemptive love, which she sang hard and in tune. But that song had its own problem: a tonal imbalance between the arrangement's grandiose, reach-for-the-stars guitar solo and its visual backdrop, pictures of Ms. Lopez in the pool with her young twins on a nice day. At the end, with a surprise appearance of the reggaeton duo Wisin y Yandel, she performed the new single "Follow the Leader." Wisin y Yandel were once going to be a regular part of this tour, as the first act of three, but dropped out two weeks before it started in Canada, citing "unresolvable issues." The Mexican singer Frankie J played the opening slot on Friday. And in four minutes they raised the competitive energy of the entire performance: stalking, Auto-Tune-crooning, hard-staccato rapping. Parts of Enrique Iglesias shows are fixed quantities: his light, quivering voice; his jeans, logger boots, military cap and stubble; his slow-dance and kiss with a hyperventilating audience member. He ran through about a dozen years" worth of soft-rock and mild dance-floor songs in English and Spanish - "Bailamos," "No Me Digas Que No," "Hero," "Dirty Dancer" (with video guest-rap by Lil Wayne), "I Like It" (with video guest-rap by Pitbull). But he spent more time attempting to make his audience feel good one to one, which meant running to the wings and smiling at fans, letting himself be touched by them, and talking to them on mike, with plenty of casual, unimpressive cursing. He wasted a lot of time and undercut his own authority; there was something watchable about this. After asking how many gay men were in the crowd, he singled out one and invited him onstage. They had a good, long chat. Just so you know: Danny's 49, single, Cuban-American, a D.J. from New York. The band started "Stand by Me," and Mr. Iglesias pushed the microphone on his new friend. When Danny finally returned to the crowd, after a long and profoundly untalented performance, Mr. Iglesias asked if the tickets had been expensive. Indeed they had, Danny confessed. "Next time," Mr. Iglesias countered, recklessly, "I promise you, I swear from the bottom of my heart, tickets will be cheaper." Jennifer Lopez and Enrique Iglesias perform Wednesday at the TD Garden in Boston; information: jenniferlopez.com, enriqueiglesias.com.