Holders Zenit St Petersburg face a tough challenge to retain the UEFA Cup after the Russian side suffered a disappointing 2-0 defeat at Udinese in the last 16 first leg last night.
Manchester City and Marseille are on course for a place in the semi-finals after home victories but Hamburg and Paris SG could not go beyond a draw in front of their own fans.
Udinese struck twice in the final five minutes to take charge of their last 16 tie against Zenit St Petersburg.
In a poor game, Udinese rarely managed to breach the Zenit defence and were forced to settle for long-range efforts that had little chance of beating Viacheslav Malafeev.
But Fabio Quagliarella popped up in the 85th minute to put them in front before Antonio Di Natale doubled the Italian's lead from the penalty spot deep in injury time to leave Zenit with an uphill battle to keep their bid for back-to-back UEFA Cup titles.
Manchester City put one foot in the quarter-finals with a 2-0 win over Danish side Aalborg at the City of Manchester Stadium.
City enjoyed a dream start when Ecuadorian Felipe Caicedo picked up Robinho's pass and turned past Michael Jakobsen in the box to slide the ball low past Karim Zaza to put his team into an eighth minute lead.
On 30 minutes, City doubled their advantage with a fine piece of individual skill from Shaun Wright-Phillips, who, after latching on to Stephen Ireland's pass, raced towards Aalborg's box to score with his right-foot.
Hughes and his men will be happy after avoiding conceding an away goal which leaves them sitting pretty in their bid to reach the UEFA Cup last eight for the first time in 30 years.
Marseille failed to take maximum advantage against 10-man Ajax as the French side failed to extend their 2-1 advantage after Gregory van der Wiel's first-half dismissal at the Stade Velodrome.
The French side had raced into a two-goal lead with strikes from Benoit Cheyrou and Mamadou Niang putting them in the box seat after little more than half-an-hour.
Luis Suarez pulled a goal back for the visitors from the penalty spot three minutes later, but Ajax were soon on the back foot again when van der Wiel was dismissed after 42 minutes for a second bookable offence.
Marseille, however, failed to make their advantage tell and Marco van Basten's team will now fancy their chances of turning the tie around at the Amsterdam Arena next week.
Galatasaray moved into the driving seat of their tie with Hamburg thanks to a 1-1 draw at the HSV Arena, despite playing most of the second half with 10 men.
Ayhan Akman gave the Turkish side the lead in the 32nd minute before Marcell Jansen equalised early in the second half.
Emre Asik was sent for an early bath in the 53rd minute, but Galatasaray held on for a draw which gives them a slight advantage ahead of the second leg in Istanbul next week.
An early goal from defender Naldo gave Werder Bremen a slender advantage to take with them into the second leg with St Etienne.
The Brazilian's strike in the 10th minute earned Thomas Schaaf's side the win at the Weser Stadion, but they may rue the many missed chances which prevented them from taking a bigger lead to France with them next week.
Vagner Love's penalty early in the second half was enough to give CSKA Moscow a 1-0 advantage over Shakhtar Donetsk.
Shakhtar dominated the game early on but could not find a goal, and they paid the price as Love lashed in the penalty five minutes after the break for his 11th UEFA Cup goal of the season.
Paris St Germain failed to make their second-half dominance count as they were held to a goalless draw by Braga at Parc des Princes.
Ognjen Vukojevic's second-half header ensured Dynamo Kiev will take a slender advantage into the second leg of their clash with Ukrainian rivals Metalist Kharkiv.
Dynamo struggled to break down their defensive-minded countrymen before Vukojevic headed in an Oleksandr Aliev corner in the 53rd minute - the first goal Metalist have conceded since the start of the group stages.