WATCH: Isco Hat Trick Leads Spain's 6-1 Rout Over Messi-Less Argentina

Watch all the highlights from Spain's sensational 6-1 rout of Argentina in a pre-World Cup friendly in Madrid.

Spain vs. Argentina was supposed to pit two of the top contenders for the 2018 World Cup title against each other in Madrid, but only one showed up.

With Lionel Messi watching from a stadium suite, sitting out a second straight game with a minor injury, Spain took Argentina to the woodshed, winning 6-1 at Atletico Madrid's Estadio Wanda Metropolitano. Isco scored a hat trick, while Diego Costa, Thiago Alcantara and Iago Aspas added the others in a statement victory for the 2010 World Cup champions.

It didn't have to be like this. Gonzalo Higuain nearly struck first, wasting a golden, albeit difficult, chance in the eighth minute. Off the counterattack, he was gifted with a perfect cross from the left from Maximiliano Meza, but the Juventus forward bounced his first-time chance just over the bar.

Spain struck a few minutes later to set off celebrations around the stadium. Diego Costa did the honors in his home arena, fearlessly racing onto a through ball from Marco Asensio and beating goalkeeper Sergio Romero and Fabricio Bustos to the ball. He slotted home from close range while colliding with Romero, scoring the goal before spending considerable time holding his knee. He returned, though, after scoring his second goal in his last three matches with Spain. Romero wasn't able to stay on, though, replaced by Willy Caballero.

Meza missed a great chance to bring Argentina level. After carrying down the center, he worked a perfectly timed combination with Giovani Lo Celso, who played him through in the center of the box. Meza's close-range chance was deflected just wide, keeping Argentina off the board.

It was Spain's turn to miss next, as Jordi Alba had chance to turn in a cross at the near post go wayward, but it didn't take long for Spain to make up for it, with help from Caballero. On the ensuing sequence off his goal kick, Isco fired home a low chance from the center of the box–off another assist from Asensio–doubling the lead in the 27th minute.

Argentina pulled one back in the 39th minute off a set piece. Nicolas Otamendi timed his leap better than Sergio Ramos for a corner kick, powering home the header off Banega's service to make it 2-1.

Spain struck twice in quick succession in the second half to put the game away. First, Isco finished after a patient Spain bided its time with Caballero out of position, as Aspas, who came off the bench, fed him for a low chance that tucked inside the right post.

Two minutes later, Thiago Alcantara got into the act, firing low from just inside the box to make it 4-1 in the 53rd minute.

Spain scored two more goals in quick succession 20 minutes later. First, Aspas raced through the center to track down David De Gea's long kick down the field. He got to it and beat the on-rushing Caballero with a low shot from 20 yards.

The next minute, Isco capped his hat trick, tucking his chance inside the left post to shockingly make it 6-1 after more Spanish pressure forced another turnover.

Isco reads the passing lane then completes his hat-trick. Argentina blown away. pic.twitter.com/ZwSHAEWACd

— Kiyan Sobhani (@KiyanSo) March 27, 2018

Here were the lineups for both teams:

⚠ OFICIAL | ¡Ya tenemos ONCE! ¡Estos son los elegidos por @julenlopetegui para medirnos a @Argentina! ¡A por todas, equipo! 💪🏻🇪🇸#VamosEspaña #MartesDePasión pic.twitter.com/KYZg2tZf5Q

— Selección Española Masculina de Fútbol (@SEFutbol) March 27, 2018

#VamosArgentina Así formará el conjunto nacional 🇦🇷 para el amistoso ante #España 🇪🇸 pic.twitter.com/wjzXZ04tIn

— 🇦🇷 Selección Argentina ⭐⭐⭐ (@Argentina) March 27, 2018

Spain and Argentina could meet again in the World Cup quarterfinals, if both win their groups and their respective round-of-16 games. Spain is grouped with Portugal, Morocco and Iran, while Argentina must navigate a foursome that includes Croatia, Iceland and Nigeria.