La Liga's second-placed side went down 3-0 at Athletic Bilbao on Sunday and now lead the Portuguese outfit by just two points.
Porto gained just 10 points despite a five-goal victory over Gil Vicente.
Barcelona extended their lead over Real Madrid at the top by 13 points to 263 after respective four-goal wins against Osasuna and Getafe.
There are no changes inside the top 10, with three representatives apiece from Spain and England, two from Germany and one from each of Portugal and Ukraine.
Benfica, 2-1 winners at Sporting Braga at the weekend, closed on the top 10 as they kept pace with Porto at the top of the SuperLiga.
They move up one place at the expense of Serie A leaders Juventus, who were held 1-1 at home by Genoa.
Lyon climbed one place to 17th thanks to Friday night's win at Valenciennes. Paris St Germain, level with Lyon at the top of Ligue 1 after a home win over Lille, stay 14th.
AC Milan moved up two places to 18th thanks to a narrow win at Atalanta. City rivals Inter are down in 28th.
The success of Lyon and Milan came at the expense of Zenit St Petersburg, who dropped two spots to 19th, and Tottenham, down one to 20th after losing 29 points.
HOW IT WORKS
To determine our Power Rankings, we use the Euro Club Index, which scientifically analyses hundreds of thousands of matches from the top divisions in all European nations as well as Europa League and Champions League games.
The Index takes into account all matches played over an eight-year period but with recent results carrying more weight than older ones.
The performance of a league's teams in the Champions League and Europa League reflects the rise or fall of the sporting level in that league.
So, for example, if English teams perform well in Europe, all Premier League teams receive a small bonus in their ECI score. The ranking and its predictive power are thus made even more accurate.