Yacine Brahimi and Moussa Marega were on target as Rio Ave held Porto to a 2-2 in Friday's Portuguese Primeira Liga encounter.
Despite the disappointment of conceding two late goals, the Dragons climbed to the summit of the Portuguese top-flight standings with 76 points from 34 matches and a point above their closest rivals Benfica.
Brahimi opened the scoring at the Estadio do Rio Ave in the 18th minute with his 11th goql of the season.
Four minutes later, Marega doubled the lead after his shot took a deflection off Junio.
Towards the end of the encounter, Porto's hopes of securing their 25th league win of the season were dashed after Rio Ave equalised in the last five minutes of the game.