The man, who has not been named, is reported to have attacked his victim near an Irish bar popular with visiting supporters.
The 23-year-old victim, was eating dinner with friends near Seville’s 15th century cathedral when the knifeman struck.
He was taken to hospital after the stabbing where he was being treated for cuts to his arm and neck last night.
In a separate incident another Celtic fan was due to appear in court after wrecking his hotel room in the Novotel Hotel in Seville after a drinking binge. The 41-year-old man was said to have caused serious damage.
However, both incidents have been seen as relatively minor as tens of thousands of Celtic supporters descend on Seville to soak up the sunshine and atmosphere in the build up to their side’s first European final for 33 years.
Spanish authorities have been preparing for the mass influx of supporters for tonight’s match against Porto and it has been estimated that as many as 55,000 Celtic supporters will be in Spain, with or without tickets or accommodation.
The exodus of Celtic fans by air is continuing unabated today as it emerged thousands of fans were catching last-minute flights to Spain for tonight’s match.
More than 40 flights are scheduled to leave Glasgow and Prestwick airports carrying around 18,000 supporters to Seville in time for tonight’s game.
Most fans are expected to fly back tomorrow following Celtic’s clash with Portuguese giants Porto at the city’s Olimpico Stadium.
British Airports Authority spokesman Malcolm Robertson said there had been a steady flow of fans at what is already a busy time of year for the airport. He said: "Tomorrow we have 65 flights coming back with supporters. Most of the people who have flown out in the past few days will be coming back at the same time.
"It could be our busiest day of the year as we have an estimated 30,000 people coming through Glasgow Airport."
The British Consul in Andalucia, Bruce McIntyre, said today he was confident the authorities would cope with the influx "I attended a meeting last night and the whole system of securing and policing the event seemed pretty well sewn up, so I’m hopeful that everything will go off without any problems."
"The fans have to do what they can and they will probably spend most of the night in the bars or in the park," he said.
Tickets for the game have been changing hands for hundreds of pounds - although officials have warned fans that they could be buying fakes. There are said to be 700 forged tickets in circulation Mr McIntyre added: "I hope they will be moderate in their partying, Seville is a fairly welcoming place but they won't take too kindly to anyone causing fights or that sort of thing."
Uefa and the Spanish police have also issued a warning to fans not to attempt to buy a ticket at this late stage, as it is likely to be a forgery. "Don't waste your money buying your tickets from touts," said the Consul. "You'll lose your money and you will not be allowed into the stadium."
In Glasgow, extra police officers are being drafted in to cope with the thousands of fans expected to crowd into pubs and clubs on Wednesday night.