Sergio Ramos's second-half penalty saw Real Madrid beat Athletic Bilbao 1-0 at San Mames as Zinedine Zidane's side remained in charge of the La Liga title race.
The Real captain stepped up to convert from the spot with just seventeen minutes to go after the referee, who had initially not pointed for a penalty, went to the TV monitor on the touchline to judge that Marcelo had been fouled.
Remarkably, that is Ramos's 10th goal of the season and his fifth in just seven games since La Liga returned to action in June. It gives Real a sizeable seven-point lead over Barcelona at the top of the table ahead of their rivals' tough-looking trip to Villarreal on Sunday night.
Meanwhile, this narrow defeat sees Bilbao stay eighth in the table, two points behind city rivals Real Sociedad in the race for the final Europa League spot with now just four games left to play for Gaizka Garitano's team.
Bilbao: Simon (7), Martinez (6), Alvarez (6)?, Berchiche (6), Capa (7), Lopez (7), Muniain (6), Cordoba (6), Garcia (7), Williams (7), D Garcia (6)
Subs: Nunez (6), Vesga (6), Sancet (6), De Marcos (6), Villalibre (6)
Away Team: Courtois (7), Carvajal (8), Militao (7), Ramos (9), Marcelo (8), Modric (8), Casemiro (7), Valverde (6), Benzema (7), Asensio (7), Rodrygo (6)
Subs: Kroos (7), Vazquez (6), Jovic (6), Junior (7)
Man of the match: Sergio Ramos
How Real ground out crucial victory in the Basque Country
Another game, another narrow, but vitally important win for Real at a ground where they have often struggled in the past, although one that will surely be of huge significance come the end of the campaign.
With second-placed Barca in action later on Sunday, the visitors knew they could lay down a marker by recording a win in the Basque Country, and that is exactly what they did thanks to a solid defensive display and the odd moment of attacking brilliance.
The first period was largely forgettable, with chances at a premium in the baking heat of San Mames, only for Madrid to step it up after the break, although they were made to wait until 20 minutes to go to make the decisive breakthrough.
At first, referee Jose Luis Gonzalez waved away Real's pleas for a penalty after Marcelo was upended by Dani Garcia, only for the official to then rightly change his mind after reviewing the incident on his pitch-side monitor.
Ramos then kept his cool from the spot to beat Unai Simon with a low shot into the bottom lefthand corner of the goal, meaning the centre back is now the first defender to score 10 times in La Liga since Mariano Pernia did it for Getafe in 2005/06.
And one suspects that come the final reckonings, the captain's ice-cool spot-kick could very well prove to be the difference between winning the title and finishing runners-up.
Bilbao host Sevilla on Thursday, while Real take on Alaves at the Alfredo Di Stefano on Friday, with both those games kicking off at 9pm.