Jose Mourinho, worried at threats from Porto fans who still resent his departure, is keeping a low profile for Chelsea's final Champions League Group H match against his former side on Tuesday.
The 41-year-old manager, who took Porto to UEFA Cup and Champions League glory in successive years before joining Chelsea last June, has asked for extra security for the game which Porto need to win to advance to the knockout round.
The English Premier League leaders are staying in Espinho, a seaside resort some 30 km from Porto and Mourinho will keep out of the public eye, sending his deputy Steve Clarke to news conferences.
Mourinho was spat on when he sat in front of Porto fans before the teams met at Stamford Bridge in September, a match that Chelsea won 3-1.
Under Portuguese law, the Porto supporter who spat should be barred from Tuesday's match, which has little significance for the London side who have already qualified top of the group.
Title holders Porto, who have struggled in the competition under Spanish coach Victor Fernandez, not only need victory but need Paris St Germain to stumble at home against CSKA Moscow in the other group match.
Failure to finish chances has been one of the Portuguese champions' biggest problems with the team relying too much on South Africa striker Benni McCarthy, who scored at Stamford Bridge.
"In every game we create six or seven chances...but we just don't have the clinical finish," Fernandez said.
Against Chelsea his side would have to overcome nerves.
"It will be a spectacular
"We will have to match them move for move and with any luck the door to qualifying will open for us."
Porto are without talismanic goalkeeper Vitor Baia, out with a thigh injury and who will be replaced by Nuno Espirito Santo.
They will also need to shake off the disappointment of the weekend's 1-0 home defeat by lowly Beira Mar, who had not won at Porto since 1977. It was their second home loss of the season.
Under Mourinho they were undefeated in Porto.
Chelsea, who aim to consolidate their five-point lead in the Premier League against champions Arsenal on Sunday, are likely to rotate several of their squad.
Mourinho has promised the other teams in the group his side will play to win but the killer instinct that has brought them four goals in five of their last seven Premier League games, may be missing.
Probable teams:
Porto: 13-Nuno Espirito Santo; 22-Georgios Seitaridis, 2-Jorge Costa, 5-Ricardo Costa, 3-Pedro Emanuel, 17-Jose Bosingwa, 18-Maniche Ribeiro, 16-Diego, 6-Costinha, 9-Luis Fabiano (or 10-Ricardo Quaresma), 77-Benni McCarthy
Chelsea: 23-Carlo Cudicini; 2-Glen Johnson, 6-Ricardo Carvalho, 26-John Terry, 18-Wayne Bridge; 19-Scott Parker; 5- Alexei Smertin, 8-Frank Lampard; 10-Joe Cole, 22-Eidur Gudjohnsen, 16-Arjen Robben.
Referee: Massimo Busacca (Switzerland)
(Additional reporting by Clare Lovell)