Not sure I'll ever know why Real Madrid changed their formation at half-time. They've been so poor since then. They've gone back to a back four since but they lost their foothold entirely.

Real Sociedad make their first change as teenage winger Ander Barrenetxea replaces goalscorer Portu.

Real Madrid are starting to get more crosses into the box but the visitors are dealing with the threat well.

A deep cross is headed just over the bar by Hugo Duro.

Real Madrid are still playing home games at the Alfredo di Stefano Stadium at their training complex while work is being done to the Bernabeu.

I had wondered if more teams would do the same in top-level football but it never happened.

As things stand, Real Madrid will be six points behind leaders Atletico Madrid - and Real Sociedad would move to within four points of the Champions League places.

Efficent. Real Sociedad goalscorer Portu hasn't had a shot saved in La Liga this season.

Close as Casemiro heads just wide from Lucas Vazquez's cross following a quickly taken corner.

Hugo Duro is a 21-year-old on loan from Getafe. He only made his Real Madrid debut a couple of weeks ago.

The hosts have a corner now.

Real Madrid replace their front line as youngsters Vinicius Jr, Rodrygo and Hugo Duro replace Isco, Marco Asensio and Mariano.

That was Portu's first headed goal in La Liga since... this fixture in February 2019.

Now Real Madrid are almost level as Toni Kroos curls just wide from Ferland Mendy's pass.

It should be 2-0 to Real Sociedad. Terrible defending by Nacho lets Portu have the ball. He tries to pick out Alexander Isak in the box but just overhits his pass. Isak would probably have scored if he'd received the ball.

Portu, who is only about 5ft 6in tall, has scored seven La Liga goals this season - as many as he managed last term.

A third corner. Nacho Monreal hammers in a low cross from the left which is turned wide by the hand of the sliding Casemiro. Probably could have been a free-kick but it's just a corner.

David Silva volleys a cross across the box but nobody is there. Real Madrid were dominant in the first half, no idea why they've changed tactics.

Real Madrid moved to a wing-back formation at the break. And it's been all Real Sociedad since the second half started. They win another corner, this time it's played back to Alexander Isak, whose shot is blocked.

Two corners in four minutes after no corners in 45 minutes.

Casemiro heads the corner into the air and Thibaut Courtois flaps at the loose ball. He spills it to Nacho Monreal, who tries to hook a close-range bicycle-kick towards goal but it's over the bar.

Bright start from Real Sociedad and Nacho puts a cross behind for a corner.

The second half begins.