Julen Lopetegui's men go into the finals in Russia as one of the tournament favourites, yet they showed little evidence of their qualification form in Krasnodar, appearing toothless in attack before Aspas's fierce 84th-minute effort.

Although Spain's knack for keeping the ball still seems in good health, they did not do a great deal with it in a particularly unimpressive first-half display.

Tunisia looked a far greater threat in the final third, but their finishing left a lot to be desired – Ferjani Sassi and Naim Sliti particularly culpable with bad misses.

Spain had a little more control in the second half and managed to carve out a few chances, David Silva and Diego Costa going close.

Tunisia nevertheless looked to have done enough to claim a commendable draw, but Aspas drilled home after Costa showed good awareness to pick him out, meaning Spain head into the World Cup in winning form and unbeaten since Euro 2016.

For all of their possession, Spain showed precious little going forward during the early stages, with Tunisia looking much brighter.

The underdogs had to rely on a Spain error for their first chance, as Thiago Alcantara's pass across the defence was cut out by Anice Badri and he managed to tee up Sassi in the middle of the area. Fortunately for Spain, the Al-Nassr midfielder's first-time effort was tame and straight at David de Gea.

Spain appeared to have been roused as they went close twice in quick succession in the 22nd minute – Rodrigo Moreno glancing a header well wide before Sergio Ramos' 30-yard drive flew just over.

That was hardly the start of an extended period of pressure, however, as Spain were lucky to not fall behind just after the half-hour mark.

Badri again caused problems on the left, crossing into the danger zone for Sliti, who inexplicably failed to hit the target from six yards.

Spain tightened up at the back upon the restart and eventually crafted a decent chance just before the hour, as Silva met Ramos' deep cross and fired wide from a tight angle.

Costa was introduced from the bench soon after and he quickly looked to make an impact, shooting from the edge of the box and forcing Aymen Mathlouthi into a fairly comfortable save.

Spain stepped things up towards the end and were rewarded for their efforts as Costa – who initially appeared to have wasted the opportunity – broke into the box and opted to tee up Aspas instead of going for goal himself, the Celta Vigo star duly blasting in left-footed.

Yet it was not a performance that will worry Portugal ahead of their World Cup opener on Friday.