LONDON - The presence of England's two leading clubs provides the Europa League with a welcome boost as it resumes this week with a pair of matches fit for the latter stages of the Champions League.

Manchester United, the reigning English champion, and Manchester City, the current Premier League leader, were arguably given the toughest draws possible after dropping down into the Europa League following surprise third-place finishes in their Champions League groups.

United plays Dutch giants Ajax Amsterdam in a match-up between two storied teams who have been crowned European champions seven times between them. The first leg is in Amsterdam tomorrow.

City, which is two points clear of United in the Premier League title race, takes on reigning Europa League champion Porto, while another standout match sees Lazio, which is third in Serie A, host 2010 winner Atletico Madrid.

The return legs are next week.

United is the biggest team to have played in the Europa League in recent years and manager Alex Ferguson is still struggling to accept his side is no longer in the Champions League after its shock exit at the hands of Swiss outsider FC Basel. "It was a massive disappointment because my feeling is that if we'd gone through, we would have gone on to the final," Ferguson said.

The Europa League, or its forerunner the Uefa Cup, is one of the few trophies never to have been won by Ferguson.

Stoke, the third English team in the knockout stage, is at home to Spanish team Valencia.

Portuguese team Sporting will have a caretaker coach in place for its first leg at Legia Warsaw tomorrow following the dismissal of Domingos Paciencia on Monday, after just half a season in charge.

In other first-leg matches, Udinese hosts Greek team PAOK and former European champion PSV Eindhoven is away at Trabzonspor.