Porto restored their four-point lead in the Portuguese Premier League after a 2-0 win over struggling Vitoria Guimaraes on Thursday in the last games before the league's Christmas break.
Porto have 37 points from 16 matches, four points clear of Nacional Madeira who won 3-0 at Boavista to regain second from champions Benfica (31 points), who needed a last-minute Nuno Gomes goal to beat Vitoria Setubal 1-0 on Wednesday.
Porto went ahead after 22 minutes when winger Ricardo Quaresma fired in from an acute angle past Guimaraes keeper Nilson before Jorginho sealed the points after combining well with South African striker Benni McCarthy after 58 minutes.
Brazilian Alexandre Goulart gave surprise title contenders Nacional Madeira the lead after five minutes.
Boavista wasted a good chance to equalise when Fary's penalty was well saved by Nacional's goalkeeper Diego Benaglio in the 27th minute before Nacional substitute Andre Pinto scored two goals in seven minutes.