By Alison Roberts
BBC News, Lisbon
Fans expected Winehouse to play a much longer song list on stage
Amy Winehouse has played the first of a series of concerts planned for this summer, at the Rock in Rio Lisboa festival in Lisbon.
Eagerly awaited by a sell-out crowd of 90,000, she disappointed a fair number with a set that started more than half an hour later than scheduled.
She suffered from hoarseness during the show - apologising for her weak voice and brandishing throat pastilles.
At one point she told the crowd that she "should have cancelled".
The singer also tripped and dropped her microphone and swore loudly several times during her performance.
The star, appeared on stage late complete with a cigarette in her hand and looking no more unsteady than usual in her high heels.
"How are you? All right? I'm so late!" were her first words to a crowd that just a few minutes before had begun to whistle.
Nevertheless the crowd cheered her enthusiastically, but it wasn't until the fourth song, Back to Black, that they really warmed up.
Soon afterwards, the two Specials numbers, Rudy and Wonderin' Now, had half the crowd dancing.
"My voice is not singing right and I can't even hold the microphone," she said. "But I wanted to be here so much."
That got one of the biggest cheers of the concert.
Fans also cheered loudly when Winehouse announced she and her husband Blake Fielder-Civil, who was "still the handsomest bloke you ever seen in your life," had recently celebrated their first anniversary.
Earlier, she changed a line in Cupid from the original "I love a girl who doesn't know I exist" to "I love a man you know who's banged up in gaol".
The Portuguese audience appreciated what humour it could catch; after she tripped and made a show of replacing one high-heeled shoe, she drew laughs with her retort that Lenny Kravitz was going to fall over too "but if he did he would be embarrassed - and I'm not".
Ironically, after apologising for her hoarseness, the singer ended with three of her strongest songs of the night: a loudly cheered Rehab, then Me & Mr Jones.
Finally there was an emphatic Valerie that had half the audience singing along with her.
Then, with a "My name is Amy Winehouse" she bowed out at the scheduled time of 11.45pm.
However, having performed a set that contained just two-thirds of the song list released by the organisers, some of the audience were less than enthusiastic.
"I was expecting something more," said Liliana Reis, 29.
"It took so much time for her to come on - people were getting impatient," agreed Alexandra Marques, 26. "And her voice really wasn't in a good state."
Their friend Marta Hugens, 26, was more scathing: "For someone who earns so much money, it shows a lack of respect for the public - although I suppose it was expected she'd make a scene."
Other spectators were more accepting. "I think she was how she is normally and that's all," said friend Anabela Costa, 27,
Winehouse has recently become very popular in Portugal and her 2006 album, Back to Black, reached number one there in February.
In its wake its predecessor Frank entered the Top 30 there for the first time.
"She's very popular at the moment. It's been a crescendo since late last year," said Jorge Manuel Lopes, a music journalist for Lisbon magazine Time Out Lisboa.
"She combines a rebellious image with a style of music that's familiar - classic soul - with a pop varnish."
Tickets for the first day of the festival sold out, unlike the other four days.
According to Lopes that was thanks to Winehouse rather than Lenny Kravitz, who played immediately after her.
"She's one of the names that will bring in most people," said Lopes.
Other big acts at the festival included Metallica, Bon Jovi, Joss Stone, the Kaiser Chiefs and Linkin Park.
Winehouse's rebellious image sits uneasily with the squeaky-clean image of the festival - whose motto is "For a Better World" and which traditionally opens with the audience waving white handkerchiefs to symbolise that.
The singer is due to play a number of other festivals across Europe this summer, including T in the Park, V Festival and Bestival in the UK, and Oxegen in Ireland and Rocke en Seine in Paris.