English Premier League champions United defeated Ajax 2-0 away from home last Thursday, and it will take a major surprise in the return fixture for Sir Alex Ferguson's experienced European campaigners not to progress.

United paid a price for their victory at the Amsterdam Arena, losing Venezuela international Antonio Valencia for up to four weeks with a hamstring injury.

Following their embarrassing group-stage exit from the Champions League, Ferguson is likely to have designs on winning the Europa League, demonstrating United's superiority to the rest of the field in UEFA's second-tier tournament.

The same applies to Premier League leaders City, who hold a 2-1 lead over Europa League holders Porto following their win in the first leg at Estadio do Dragao last week.

City stars Mario Balotelli and Yaya Toure were reportedly subjected to racist abuse by the home fans in Portugal, and the English club are likely to offer a heated welcome to the Liga Sagres champions when they run out at Etihad Stadium on Wednesday.

With the draw for the last 16 made in advance, United know they will face either Lokomotiv Moscow or Athletic Bilbao of Spain in the next round.

Russian Premier League side Lokomotiv hold a 2-1 lead over Athletic, but the Copa del Rey finalists are more than capable of overturning the deficit at their Estadio San Mames fortress.

City will play either Legia Warsaw or another Portuguese team, Sporting Lisbon, who drew 2-2 away to their Polish opponents in the first leg.

Elsewhere, La Liga side Valencia hold a 1-0 advantage going into their home match against Premier League team Stoke City, while Turkish side Besiktas are 2-0 up and at home to Sporting Braga of Portugal.

Rubin Kazan of Russia must overturn a 1-0 deficit away to Greek club Olympiakos.

AZ Alkmaar, who lead by the same margin, make the short trip from the Netherlands to Belgium, where they tackle Anderlecht.

Metalist of the Ukraine appear to be through already following their 4-0 win away to Red Bull Salzburg, while Atletico Madrid are in charge thanks to their 3-1 victory at Lazio.

Steaua Bucuresti of Romania trail 1-0 and must visit Twente of the Eredivisie.

Another Dutch club, PSV Eindhoven, are 2-1 up ahead of the arrival of Turkish side Trabzonspor.

Standard Liege of Belgium have home advantage against Polish outfit Wisla Krakow, with the score in their tie level at 1-1.

PAOK Salonika of Greece will look to build on their credible 0-0 draw away to Italian side Udinese.

And finally, Bundesliga club Hannover take a 2-1 advantage with them in their trip to face Belgian side Club Brugge.