LONDON (AP):

It's been the season of the underdogs in the FA Cup, yet the presence of England's four Champions League entrants gives the famous competition an ominous look heading into the fifth round this weekend.

Only seven Premier League teams made it out of a shock-filled fourth round last month, but the survivors include Manchester United, Manchester City, Arsenal and - only just - Chelsea.

The European champions were forced into a replay against third-tier club Brentford on Sunday to confirm their place in the fifth round, while the other big three were given favourable home matches in the draw for the last 16.

There could still be room for surprises, however, with Luton bidding to become the first non-league club in 99 years to reach the quarter-finals when they take on second-tier club Millwall at Kenilworth Road.

And third-tier team Oldham - conquerors of Liverpool in the last round - look to bring down another giant from Merseyside when Everton, who are sixth in the Premier League, visit Boundary Park.

The exploits of Luton and Oldham, who have fallen on hard times since being relegated from the Premier League in the 1990s, has given the FA Cup a major shot in the arm. It ensured the world's oldest knockout competition remained in the spotlight in the season its rival, the League Cup, has taken centre stage with fourth-tier club Bradford's shock run to the final at Wembley Stadium, which takes place on February 24.

Luton has been the biggest so-called 'giant-killer', eliminating Norwich 1-0 in the fourth round to become the first non-league side to beat a top-flight team in the FA Cup since 1989.

Only six other teams from outside England's Football League have made it this far in the competition since World War II.

"It's such a buzz," Luton captain Ronnie Henry said. "When you're young, you dream of winning the FA Cup. Who knows?"

Standing in their way now are Millwall, a match which brings back memories of an unsavoury meeting between the two teams in the FA Cup in 1985 - at the height of English football's era of hooliganism.

On that occasion, which has subsequently been dubbed the 'Kenilworth Road Riot', Millwall fans went on to the pitch after the final whistle and threw chairs at police officers. A total of 47 people, including 33 police officers, were injured and 31 people were arrested and Luton reacted by banning away supporters from its ground for four years.

"I think we've moved on as a society, let alone moved on in football," Luton chief executive Gary Sweet said.

Luton are currently seventh in the Conference Premier, the fifth tier of English football.

Everton are determined not to slip to the same fate that befell Liverpool, who appeared to underestimate the threat posed by a fired-up Oldham last month.

"You know you're going to be playing in difficult conditions and sometimes things don't go for you," Everton defender Leighton Baines said, "but we've just got to go there and be professional.

"You've got to make the right decisions and not get caught up in the different style of play which they'll try and force on the game. We need to play our own game and if we can get the first goal, then that can make a big difference."

Oldham bizarrely fired their manager, Paul Dickov, soon after the win over Liverpool because of the team's poor run of form in the league.

Also tomorrow, Arsenal host Blackburn and will be looking to stay in the hunt for their last realistic hope of silverware this season.

Arsene Wenger's side, without a trophy since 2005, are still in the Champions League but are one of the outsiders, especially since they face Bayern Munich in the last 16.

Third-tier club MK Dons host second-tier team Barnsley in tomorrow's other game.

On Sunday, Man City are at home to Leeds, who beat Tottenham in the fourth round, and Wigan visit Huddersfield, who play in the second-tier League Championship.

The only all-Premier League match sees Man United host Reading on Monday.