Liverpool, once the pre-eminent team in England, are 20 points behind Premiership leaders Manchester United ahead of a weekend of matches which see top flight and First Division clubs enter the world's oldest senior knockout football tournament.

To make matters worse for Houllier, Liverpool are set to be without captain Steven Gerrard although Michael Owen could return from injury as a substitute.

In the tradition of Cup upsets, Sunday's match is taking part at the lower-ranked club's ground.

And although Third Division Yeovil no longer play on a sloping pitch their compact Huish Park ground could well test the resolve of players used to operating in grander surroundings.

Former Liverpool captain Emlyn Hughes is in no doubt about the importance of Sunday's match. "It's a big game for the club and a big game for Gerard Houllier," Hughes told Thursday's Daily Mirror.

"Liverpool will be looking to win the FA Cup and after that their only other chance of winning a trophy this season is the UEFA Cup.

"If they lose to Yeovil it could be a catastrophe for them. Gerard's job could be on the line," added Hughes, whose trophy-laden spell as Liverpool captain included an FA Cup final win against Newcastle in 1974.

Despite spending heavily in the transfer market, Houllier has failed to return the English title to Anfield after a gap of nearly 14 years.

Although Liverpool are noted for rarely sacking managers reports from Merseyside suggest the board's patience is wearing thin.

Yeovil's place in Cup lore was secured back in 1949 when, as a non-league side, they defeated then mighty Sunderland in the fourth round.

Now fifth in the Third Division, they are managed by former Latvia coach Gary Johnson who insists his team are ready to add to the 20 League scalps collected in Cup competition by Yeovil's non-league predecessors.

"We want to win. I won't be saying, 'Go out there lads and just enjoy it.' That's not what we are about," Johnson insisted.

"If these lads are playing tiddlywinks or Liverpool in the cup they want to win. They are so focused."

Another upset could take place at Aggborough on Saturday where Third Division Kidderminster, managed by former Liverpool midfielder Jan Molby, face Premiership basement club Wolves.

There are several all top-flight ties with Arsenal, Cup holders for the past two seasons, away to second from bottom Leeds on Sunday.

If Arsene Wenger's men emerge victorious at Elland Road it could mark the start of an historic Cup campaign for the Londoners.

No team in the tournament's history have played in four successive finals while the last team to win the trophy three times in a row were Blackburn Rovers between 1884 and 1886.

Sunday also sees Premiership leaders Manchester United away to mid-table Aston Villa. United's tally of 10 Cup successes is a tournament record but they have not lifted the trophy since their treble-winning season of 1999.

When the clubs last met at the same stage of the competition in the 2001-02 season United overcame a 2-0 deficit to win 3-2 with Dutch striker Ruud van Nistelrooy scoring twice.

Long-serving Villa chairman Doug Ellis, 80 in February, is not alone among the Birmingham club's supporters in wanting revenge.

"No-one needs reminding what happened when United came to Villa Park at the same stage two years ago. The memory of losing after holding a two-goal lead still leaves a bitter taste," said Ellis.

"Although we are under no illusions it will be any easier this time, the fans can be rest assured our players will be intent on revenge."

Southampton, last season's beaten finalists, are at home to Newcastle on Saturday.

Both sides currently have 26 league points - the same as Liverpool - and the Cup represents their best

chance of silverware.

Other potential banana skin contests see big-spenders Chelsea at First Division Watford, Portsmouth hosting Second Division Blackpool and another struggling Premiership side, Tottenham, taking on First Division London rivals Crystal Palace.