Porto have been deducted six points by Portuguese football authorities for attempting to fix league matches.
The league's disciplinary committee ruled that Porto tried to bribe referees in two matches in the 2003/04 season, and, as well as the points deduction, have been fined €150,000 (£119,000) and barred chairman Jorge Pinto da Costa from the bench during matches for two years.
The league's disciplinary committee has also relegated Boavista to the second division and fined the club €180,000 (£143,500) after being found guilty of trying to coerce referees in three games in the 2003/04 season.
The club's chairman at the time, Joao Loureiro, was suspended for four years and fined €25,000 (£19,000).
Leiria, also a top-flight club but unable to avoid relegation this year, were found guilty of trying to bribe match officials the same season and was docked three points while fined €40,000 (£31,000). The club's chairman was suspended for one year.
Five referees have also been suspended for up to six years after being found guilty of corruption.
The sanctions are to take effect within three working days unless appeals were lodged. All three clubs denied the charges.
The points deduction will not prevent Porto from lifting their third consecutive league title, as the club will still maintain a 14-point lead going into Sunday's final fixtures.
The committee's president Ricardo Costa said officials questioned 85 people during the investigation and compiled a case file containing almost 1,000 pages.
He said in a televised press conference: "These decisions were unanimous. Five people agreed with the penalties to be applied."

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Chelsea 1-0 Man Utd - Ferguson
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West Ham 1-2 Everton - Moyes
Wigan 1-1 Fulham - Martinez
Wigan 1-1 Fulham - Hodgson
Hull 2-1 Stoke - Horton
| Time | Fixture |
|---|---|
| Sunday 8th November | |
| Barclays Premier League | |
| 13:30 | Hull vs Stoke |
| 15:00 | West Ham vs Everton |
| 15:00 | Wigan vs Fulham |
| 16:00 | Chelsea vs Man Utd |
| Monday 9th November | |
| Barclays Premier League | |
| 20:00 | Liverpool vs Birmingham |
| Saturday 21st November | |
| Barclays Premier League | |
| 12:45 | Liverpool vs Man City |
| 15:00 | Birmingham vs Fulham |
| 15:00 | Burnley vs Aston Villa |
| 15:00 | Chelsea vs Wolverhampton |
| 15:00 | Hull vs West Ham |
| 15:00 | Sunderland vs Arsenal |
| 17:30 | Man Utd vs Everton |
| Sunday 22nd November | |
| Barclays Premier League | |
| 13:30 | Bolton vs Blackburn |
| 15:00 | Tottenham vs Wigan |
| 16:00 | Stoke vs Portsmouth |
| Wednesday 25th November | |
| Barclays Premier League | |
| 19:45 | Hull vs Everton |
| 20:00 | Fulham vs Blackburn |
| Saturday 28th November | |
| Barclays Premier League | |
| 15:00 | Blackburn vs Stoke |
| 15:00 | Fulham vs Bolton |
| 15:00 | Man City vs Hull |
| Time | Result |
|---|---|
| Saturday 7th November | |
| Barclays Premier League | |
| Wolverhampton 1 - 4 Arsenal | |
| Man City 3 - 3 Burnley | |
| Tottenham 2 - 0 Sunderland | |
| Blackburn 3 - 1 Portsmouth | |
| Aston Villa 5 - 1 Bolton | |
| Wednesday 4th November | |
| Barclays Premier League | |
| West Ham 2 - 1 Aston Villa | |
| Sunday 1st November | |
| Barclays Premier League | |
| Birmingham 0 - 0 Man City | |
| Saturday 31st October | |
| Barclays Premier League | |
| Man Utd 2 - 0 Blackburn | |
| Sunderland 2 - 2 West Ham | |
| Portsmouth 4 - 0 Wigan | |
| Bolton 0 - 4 Chelsea | |
| Stoke 2 - 2 Wolverhampton | |
| Fulham 3 - 1 Liverpool | |
| Burnley 2 - 0 Hull | |
| Everton 1 - 1 Aston Villa | |
| Arsenal 3 - 0 Tottenham | |
| Sunday 25th October | |
| Barclays Premier League | |
| West Ham 2 - 2 Arsenal | |
| Man City 2 - 2 Fulham | |
| Liverpool 2 - 0 Man Utd | |
| Bolton 3 - 2 Everton | |
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