The Croatian midfielder neatly tucked the ball into the net from close range after the Montenegrin, Dejan Savicevic, made a great late run into the box before laying off a perfect pass.
Boban's goal sent PSG to their first defeat in the tournament after eight victories and a draw against Barcelona in one leg of the quarter-finals. After a fairly open first half, defences dominated in the second. The closest the French came to scoring was in the 83rd minute when David Ginola hit the crossbar.
Ajax moved a step closer to their first Champions' Cup final since they won the trophy for the third consecutive season in 1973 with a goalless draw away to Bayern Munich in the other semifinal. The Dutch outclassed a Bayern side that suffered for the absence of key players including Lothar Matthus. Despite home advantage the three-times winners Bayern only looked dangerous on the counter-attack.
The return legs are in two weeks' time.