Just two top-flight teams in Europe are still unbeaten – and since FC Porto and SL Benfica are tussling for the Portuguese Liga, neither can afford to let that record slip.

Since the turn of the year FC Barcelona, Olympiacos FC, Anorthosis Famagusta FC and Albania's KS Skënderbeu have all suffered first league defeats, leaving Porto and Benfica as the only clubs with zeroes in their loss columns with ten games to go. They have been neck and neck since the fifth round of matches in late September, drawing 2-2 when they met in mid-January and both being held on 10 February.

Porto coach Vítor Pereira, whose side lead by three on goal difference, said: "It's been a great fight between the two teams and I believe it will continue for a while."

His charges' 2-1 weekend home win against Rio Ave FC extended their unbeaten Liga run to 33 games, going back to 29 January 2012. In fact, Pereira's 50 league matches in charge have brought 39 wins, ten draws and a solitary defeat, 3-1 at Gil Vicente FC.

That is not to say it has been easy. Against Rio Ave, after half an hour Jackson Martínez missed a penalty and the visitors soon went ahead. However, Martínez levelled on half-time and won it with 12 minutes left, his 22nd Liga goal in 20 outings.

"The league is approaching a decisive phase," said Pereira. "Only a united team could have turned that game. I appealed to the soul of the team, we realised that the boys were tired and lacking ideas. But you also need to know how to win with character. It has exactly the same value as winning with a great display."

Meanwhile, Benfica are unbeaten in all 28 domestic games in 2012/13 – 23 wins, five draws – and their only two losses came in the UEFA Champions League. Even so, coach Jorge Jesus is aware that at this stage last year his side, having surrendered a five-point advantage, were caught by eventual champions Porto, who made it eight titles in ten years.

"We are now a much stronger team mentally," Jesus said. "The team show no anxiety and that helps us be calmer so we can control matches. And then we can make the difference when teams allow us to reach the last third of the pitch."

His men overcame surprise third-placed outfit FC Paços de Ferreira 3-0 in Lisbon on Sunday to make it 50 Liga goals for the campaign in response to Porto's victory, and Jesus added: "Given the spell Benfica and Porto are having, it is dangerous to drop points."

That will probably be the case right until the top two face off in their penultimate league fixture in mid-May. There is no rest outside the Liga either as Benfica are in the UEFA Europa League and both domestic cup semi-finals, while Porto have the small matter of an ongoing UEFA Champions League tie with Málaga CF.