Birmingham registered one of the great achievements in the club's history as they saw off Portuguese side CD Nacional 3-0 to qualify for the group stages of the UEFA Europa League.
Following a goalless first leg in Madeira in which Blues hit the woodwork three times, the midlands outfit struck twice in nine first-half minutes to take firm control of the tie.
Nathan Redmond, David Murphy and Chris Wood scored the goals as Chris Hughton's men claimed a relatively straightforward win.
The visitors' clearest opportunity to strike an early blow came as Curtis Davies misjudged a long goal-kick from Rosa Elisson. Mateus nicked in to nudge the ball past keeper Boaz Myhill on the edge of the box, only to be forced back to Daniel Candeias - who curled wide.
It was certainly against the run of play which Blues opened the scoring in the 15th minute, but it was a goal of pure quality. Left-back Murphy fed Redmond and the youngster skipped past Luis Alberto before drilling into the bottom corner from 20 yards.
The goal certainly settled Blues and lifted the home support, who were in dreamland soon after. Jean Beausejour's inswinging corner was met at the near post by a combination of Murphy and Alberto and the ball found the net via the crossbar.
Birmingham were in full swing and Wood was only denied a third by a last-ditch block from Zarko Tomasevic.
Nacional remained a threat in attack but it was Blues who went close to scoring every time they went forward, Chris Burke seeing his effort cleared off the line by Ferreira Claudemir before Adam Rooney's side-footed volley forced a solid save from Elisson.
Rooney enjoyed a clear chance to wrap matters up in the 77th minute but, with Wood in acres of space, opted to shoot straight at Elisson.
Redmond then curled against the far post before Wood, who had minutes earlier seen his attempted chip saved by Elisson, rounded off a memorable night from close range following a swift counter.