Benfica lost further ground on Porto after they were held to a 1-1 draw against Belenenses while Sporting Lisbon won on Saturday.
Benfica are now five points behind defending champions Porto after their latest slip-up in the Portuguese top-flight, with the result leaving them in fifth position.
Jorge Jesus' side, who have endured a mixed start to the season, claimed the lead after just 18 minutes when Paraguay forward Oscar Cardozo was on target.
Cardozo's goal - his second in as many matches - only gave Benfica the lead for 13 minutes, though, as Mali midfielder Mourtala Diakite popped up with an equaliser.
And, despite Jesus chasing the game with a range of substitutions, Benfica were held by a side who are in the relegation zone and have won just once in six league matches this season.
Sporting Lisbon are just two points behind Porto after climbing to second with a 2-1 away win against 10-man Braga.
Colombian Fredy Montero gave Sporting the lead after just five minutes, although Alan produced a leveller before the break.
The straight red card shown to Aderllan Santos in the 31st minute harmed Braga's cause, however, and they were the victim of a late blow as Cedric Soares netted a winner with just four minutes to play.
Elsewhere, rock-bottom Pacos de Ferreira notched their first win of the season with a superb 4-3 triumph at Maritimo, a match in which they trailed three times.
Derley's double and an Igor Rossi strike saw Pacos trailing 3-2 with just under 30 minutes to play, but the visitors - who had earlier scored through Rui Caetano and Manchester United loanee Bebe - staged a fightback.
Substitute Manuel Jose levelled proceedings with 21 minutes to play before Igor Rossi turned villain as his own-goal in the 89th minute handed the strugglers an unlikely win.
Other results on Saturday saw Nacional defeat Rio Ave 3-0, while Estoril triumphed 2-1 at Olhanense and Academica and Arouca played out a goalless draw.
|Coach: Jorge Jesus|
for L. Marković 46'
for N. Matić 64'
for Lima 80'
|Champions League Final: Luis Enrique worried about Juve, Italian fan nears end of Berlin bike ride|
|Essien joins Panathinaikos|
|Blatter in profile: A look back on 17 years at the top of world football|
|Demichelis set for international retirement after Copa|
|Football world reacts to Blatter resignation|
|Blackpool turn to McDonald|
|Blatter resignation: How the FIFA scandal unfolded|
|Ancelotti rejects Milan approach|
|Platini: Blatter resignation ´the right decision´|
|Swiss Attorney General: Blatter not under investigation|
|Blatter resignation can inspire FIFA change - Scala|
|Mohsni faces lengthy SFA ban|
|Sepp Blatter: Resignation speech in full|
|Blatter to resign as FIFA president|
|Adkins named Sheffield United manager|
|Juve talks ongoing - Witsel|
|Costa has no intention of leaving Chelsea|
|Ligue 1: Paris Saint-Germain season review - Blanc´s men make history|
|Luis Enrique ´worried´ by Juve|
|Mourinho: Costa happy at Chelsea|
|Mourinho hits out at ´unacceptable´ Loftus-Cheek display|
|Inter an ´option´ for Richards|
|Messi: Off-field relationship with Neymar and Suarez key|
|Remy rifle seals Sydney win for Chelsea|
|Messi could replicate Bilbao goal - Luis Enrique|
|Liverpool mauling a boost in transfer market, says Stoke chairman Coates|
|Adkins: Football can learn a lot from rugby|
|Celtic swoop for City defender Boyata|
|Xavi out to sign off in style at Barca|
|Criscito and Poli leave Italy squad|
|Lacazette plays down ´unfounded´ PSG rumours|
|Lloris: No buy-out clause in Tottenham contract|
|Newcastle released Taylor and Gutierrez in same phone call|
|Alba signs new Barcelona deal|
|Benteke coy on Villa future|
|FIFA denies Valcke involvement in $10million payment|
|Brazil selection never influenced, says technical director|
|Pogba doing ´great things´ and will get better, says Deschamps|
|Bundesliga: Borussia Dortmund season review - Klopp endures rocky farewell|
|Adler ´aged three years´, Labbadia ´extremely proud´ of Hamburg|
|Colombia squad settles in Argentina|
|Balotelli ´a target´ because of Liverpool form - Richards|
|Bosnich: If I´d listened to Terry I would have avoided drugs|
|Luiz Gustavo ruled out of Brazil´s Copa America squad|
|Mexico confirm Copa squad|
|Pogba ´very happy´ at Juve|
|Pogba can be Europe´s greatest - Pirlo|
|Pinedo stays in Argentina, Bolivia captain Raldes in Copa America squad|
|Quinteros cuts Banguera, Hidalgo for Chile showpiece|
|Injured Gonzalez misses Copa America, Venezuela finalise youthful squad|
|Champions League Final: Buffon plays down Juve hopes, Iniesta doubtful|
|Karlsruher 1 Hamburg 2 (2-3 agg): Muller strike ensures survival|
|CONCACAF official Sanz banned by FIFA|
|Gourvennec shuns admirers with Guingamp extension|
|Pastore signs PSG extension|
|Morel swaps Marseille for Lyon|
|Watford sign Austria defender Prodl|
|Monaco confirm Berbatov departure|
|Peru v Mexico: Herrera confident as Copa preparations continue|
|Injury rules Dost out of Netherlands friendlies|
|Koeman must strengthen attack for Europa League challenge - McMenemy|
|Wilshere apologises for Spurs taunts|
|Marchisio: No fear ahead of Barcelona clash|
|Klopp to take break after leaving Dortmund|
|Champions League win would be ´more than extraordinary´ - Allegri|
|Charity calls for education after Leicester ´racist orgy´ claims|
|Taylor agrees Swansea deal|
|Sevilla snare Krohn-Dehli|
|Coloccini hails Gutierrez after ´perfect´ Newcastle finale|
|Benitez excited by Madrid opportunity|
|Sampaoli confirms final Chile squad for Copa America|
|Clement ready to go it alone at Derby|
|Mihajlovic confirms Sampdoria exit|
|Brentford turn to Dijkhuizen|
|Usami, Moto to lead Japan qualifying threat|
|Vieira ´the best bet´ for Newcastle - Bernard|
|´We´ll see what happens with my future´ - De Gea|
|Klinsmann: Guzan will start at Gold Cup|
|Alves wants Barca extension not PSG - Blanc|
|Derby appoint Paul Clement as head coach|
|Karlsruher ´can only win´ - Kauczinski|
|Ronaldinho causes stir with disallowed goal|
|Szczesny plans Arsenal stay|
|Pioli: Lazio deserve Champions League qualification|
|Pablo Aimar makes River Plate return|
|MLS Review: Seattle leave it late against Red Bulls|
|Wenger: Arsenal won´t spend big|
|Police to investigate Rangers-Motherwell fight|
|´I will definitely stay´ at City - Toure|
|Champagne backs Blatter to reform FIFA|
|Honduras 2 El Salvador 0: Penalty, goal and red card to Lozano|
|Mancini wants Icardi to stay|
|Sampdoria set to speak on Mihajlovic future|