Bayern Munich had to scrap for a 2-2 draw at Aberdeen and Atletico Madrid lost 1-0 at Bolton Wanderers as the UEFA Cup heavyweights struggled in last 32 first-leg matches on Thursday.
Four-times European champions Bayern twice came from behind at Pittodrie as the Scottish Premier League side threatened to repeat their achievement from 1983 when they stunned the Bavarians 3-2 in the quarter-finals of the Cup Winners' Cup.
Atletico suffered their first away defeat in Europe this season, Senegal striker El Hadj Diouf's 74th-minute goal handing Bolton victory just seconds after the Spanish side's Argentine striker Sergio Aguero had been sent off at the Reebok Stadium.
Two-times winners Tottenham Hotspur won 2-1 at Slavia Prague, Fiorentina overcame Rosenborg 1-0 in Norway, Hamburg SV took command of their tie against FA Zurich with a 3-1 win in Switzerland and Benfica beat Bundesliga strugglers Nuremberg 1-0 in Lisbon.
Two on-loan players from English Premier League clubs provided the catalyst for a pulsating Aberdeen performance in which they combined swift counter-attacks with gritty defence in the face of greater Bayern possession.
Striker Omatsone Aluko, on-loan from Birmingham City, set up 18-year-old Josh Walker, on-loan from Middlesbrough, to curl in a fine opening goal from 25 metres.
Aluko also produced a finish of the highest calibre just before halftime, dinking the ball past a Bayern defender before volleying sweetly past stand-in keeper Michael Rensing, deputising for the ill Oliver Kahn.
In between, Miroslav Klose hauled Bayern level and their second equaliser on 55 minutes came after Alan Maybury had handled Ze Roberto's cross. Hamit Altintop's penalty was parried by keeper Jamie Langfield but the midfielder converted the rebound.
Aberdeen came into the game having leaked nine goals in their previous two games but their performance delighted coach Jimmy Calderwood.
"We deserved more to be honest," he told BBC Scotland. "To draw against a team at this level says a lot about us."
Spurs appeared set for a comfortable win in Prague against a side they beat home and away in the competition last season but a spirited final 20 minutes gave Slavia some hope for the return in London.
Goals from Bulgaria striker Dimitar Berbatov and Robbie Keane had Tottenham 2-0 up after half an hour but Juande Ramos's side proceeded to spurn a host of chances to increase their advantage.
The Czech side pulled a goal back on 69 minutes when their former keeper Radek Cerny dropped a cross and David Strihavka tapped in and the hosts went close to an equaliser when Erich Brabec powered a header against the crossbar.
Fiorentina striker Adrian Mutu pounced from close range for the only goal on 16 minutes to sink Rosenborg while Portugal's international striker Ariza Makukula, who joined from Sevilla last month, struck two minutes from halftime for Benfica's winner against Nuremberg.
Nuremberg were playing their first game since appointing Thomas von Heesen as coach on Tuesday after firing Hans Meyer the day before.
The final is in Manchester on May 14.