This was Newcastle’s first European campaign since 1977.
It was also their first since the ban on English clubs playing on the continent after the Heysel Stadium disaster had been lifted in 1990.
There was still a reasonable police presence in Bilbao on what was a national holiday.
Supporter Karl Pedley recalled how Newcastle fans were accompanied into San Mames by “full riot police, some of whom were armed”.
However, just a few minutes into the game, he noticed how “a number of them had sat down with their helmets and pads off, and were enjoying what we were doing”.
There was no edge, even after Newcastle were defeated 1-0, and Athletic fans invaded the pitch and sprinted towards the away end to applaud the travelling support.
Newcastle supporters responded by chanting “Athletic! Athletic! Athletic!” – but that was not the end of the matter.
“The police held us back for a short while and took us down a long concrete staircase into the main road,” Pedley said. “All we could see at the bottom was this mass of red and white.
“They brought us down in single file and let us go. We thought ‘oh, here we go.’ But all the Athletic fans wanted to do was shake your hand, pat you on the back and take you to a bar. It was as if they were like ‘adopt a Geordie’.
“I don’t think there was anyone in a Newcastle United shirt who didn’t get fed and watered that night. They were just really appreciative that we were enjoying their city.”
Chants were exchanged as Newcastle fans taught Athletic supporters – among others – “walking in a Keegan wonderland” and “he gets the ball and scores a goal, Andy, Andy Cole”.
Shirts and scarves were even swapped and this remains, possibly, the only occasion where a number of Newcastle supporters wore red and white, which are also the colours of bitter rivals Sunderland.
One such Athletic shirt remains a cherished memento from an away day that Newcastle fan Philip Long will never forget.
“It’s still in the wardrobe with a couple hundred of my Newcastle tops,” he said. “I’ll never let go of it.”