A mature, modest and (almost) scandal-free George Michael took the stage in his first solo concert in 15 years. But the pop star couldn't resist making another controversial dig at George Bush.

At the end of the first set Michael sang his 2002 controversial anti-Bush song "Shoot the Dog."

• Video: See George Michael perform

During the number, an enormous balloon depicting a cartoon-ish George Bush rose out of centre stage, drawing whoops and yells from the crowd. But the real surprise came when Michael leaned down to unzip the balloon's trousers, and out popped a British bulldog draped with the UK flag. The dog was stuck to the balloon's inflated crotch, wagging its tail.

George Michael sang his greatest hits to 18,000 fans packed into Barcelona's Palau Sant Jordi arena at the start of his new European tour.

With no new album to promote, the concert indulged an audience of mostly long-time fans with favorites like "Faith," "Father Figure" and "Too Funky," while also including newer hits.

In February 2005 Michael announced the end of his pop career to the international media, and the irony that less than two years later he's here back on the stage, singing all his pop standards once again, was not lost on him.

The fans, however, aren't holding any grudges for what Michael has dubbed his "being such a tease." They clapped, cheered, swayed and sang their way through two-and-a-half-hours of ballads, covers and dance tunes.

The early part of the show suffered from a few low moments when it seemed as though Michael's slow clapping and side-to-side sway-and-shuffle style of dancing weren't going to be enough to keep the crowd engaged throughout the night. But after a few songs the singer seemed to warm up to his audience, dominating the stage and obviously happy to be performing again.

"Its coming back, its coming right back," he called out to the crowd just before launching into the unexpected second sing-through of "Too Funky", a technical glitch Michael handled with ease. "Well just go along with this," he said as both he and the audience began to sing the familiar lyrics for the second time in a night.

Michael skyrocketed to fame in the 1980s as the creative half of the duo Wham! before staking out on a Grammy-winning solo career. His next album, due out in November, is called simply "25" and, like the tour it is named after, is a celebration of the highlights of Michaels quarter century in pop.