Benfica have fallen 10 points behind Liga Sagres leaders Porto after being held to a 1-1 draw at home by lowly Portimonense on Sunday.Benfica, who suffered an earlier setback when they were felled by Sporting Braga last weekend, looked in all sorts of trouble as Ricardo Pessoa put the visitors ahead from the penalty spot in the 28th minute.Nuno Gomes equalised 12 minutes from injury time, but Benfica's desperate attempts for a late winner were thwarted by Portimonense goalkeeper Hugo Ventura.Benfica remain second on the table, now 10 points adrift of unbeaten Porto, while Portimonense move to second bottom and edge within five points of escaping the relegation zone.Elsewhere, Nacional's hopes of a European berth took a blow when they were held to a 1-1 draw at home by Academica.Orlando Sa put Nacional ahead on the hour with his first goal since November, but Brazilian striker Laionel stole a point for the visitors with an injury-time equaliser.Finally, Maritimo moved nine points clear of the relegation zone with a comprehensive 3-0 victory at Naval de Maio, who slump to the bottom of the table.On-loan Atletico Mineiro striker Kleber (23), Angolan forward Djalma (25) and Senegalese striker Babacar Diawara (87) all got on the scoresheet for the visitors, who leap to 12th and erase back-to-back losses to Benfica and Rio Ave.Sunday's scheduled clash between Olhanense and Braga was postponed until March 27.