MADRID, Sept. 25 (Xinhua) -- Atletico Madrid won the city derby against Real Madrid on Sunday night to end their neighbors' unbeaten start to the season and allow FC Barcelona to take over the leading position of La Liga. Here are some things we learned in the sixth round of matches.

1. Atletico unlock Real Madrid with ease

Atletico Madrid enjoyed a flying start to lead the derby against Real Madrid 2-0 after less than 20 minutes.

First Alvaro Morata flicked home Samuel Lino's cross from the left, and then Antoine Griezmann headed in after Saul's cross - also from the left.

Real Madrid reacted with a goal from Toni Kroos, but another Morata header made it 3-1 a minute into the second half.

Morata's second goal came from yet another Saul cross from the left and highlights how Real Madrid didn't learn from their earlier errors. In these three occasions, right back Lucas Vazquez was exposed without support for an overlapping player to put the ball into the Real area, and three times central defenders Antonio Rudiger and David Alaba failed to mark the striker, showing Real Madrid's awful defending.

2. Barca not written off with their firepower

FC Barcelona looked to be dead and buried as they trailed 2-0 at home to Celta Vigo with just 10 minutes left to play, and Celta's lead could have been bigger with some better finishing.

The missed chances turned out to be decisive as Barcelona came back in the last 10 minutes to claim an unlikely 3-2 win, with Robert Lewandowski scoring twice and Joao Cancelo arriving from deep to score the winning goal in the 89th minute.

Cancelo was impressive once again and his presence gives Barca another attacking option to add to Lewandowski, Gavi, Ferran Torres, Joao Felix and Raphinha.

They didn't play especially well on Saturday, but Barca's attacking options mean you can never say it's game over.

3. Impressive Girona go second with favorable calendar ahead

Girona go into the midweek round of games second in La Liga with five wins and a draw and 16 goals scored in their first six matches.

Michel's side continue to play attractive football with winger Savio really impressing, but what is so refreshing about Michel's side is that other players, such as David Lopez and Yangel Herrera have previously been journeymen for sides playing in the lower half of the table.

Michel's success is that he has the team playing open flowing football. A look at Girona's forthcoming games, with clashes against Villarreal, Cadiz, Almeria and Celta on the horizon, implies they can stay near the top of a long time to come.

Next Saturday's game at home to Real Madrid promises to be unmissable.

4. Athletic Bilbao not missing Martinez

Goals from Inaki Williams and Oihan Sancet gave Athletic Bilbao a routine 2-0 win away to Alaves to leave them fourth in the table and confirm the club's best start to a season in this century.

Athletic's main problem in recent seasons has been how to turn possession into chances and goals, but with Sancet, Williams and Gorka Guruzeta all starting the season well, that hasn't been an issue so far in the campaign.

Many suspected that the loss of Spain international defender Inigo Martinez to Barcelona over the summer could weaken the Basque club's defense, but so far Aitor Paredes has performed admirably in his place.

This season has seen Athletic win 2-0 away to Alaves and Osasuna and draw 0-0 in Mallorca, and three consecutive clean sheets away from home is a sign that they are not missing Martinez.