Krasnodar (Russia), Jun 10 (IANS): Spain wrapped up their preparations for the 2018 World Cup here with a hard-fought 1-0 victory over Tunisia, getting a late goal by substitute Iago Aspas in what was La Roja's worst performance under head coach Julen Lopetegui.

Trouble signs that had reared their head in Spain's 1-1 draw against Switzerland last weekend were more evident at Krasnodar Stadium, where the Spaniards dominated possession but lacked scoring precision and at times were tentative with their passing and sloppy in defence on Saturday, reports Efe.

The Spainiards had the ball around 72 per cent of the time, but even so found themselves in a dog fight against a hard-nosed team that came into the match with a nine-game unbeaten streak.

Tunisia looked to apply pressure and seek out opportunities on the counter-attack in the first half.

But although the North Africans managed to find space at times behind defender Alvaro Odriozola they were unable to get anything past David de Gea, with Tunisian midfielder Naim Sliti sending one shot over the crossbar and failing to convert a second opportunity on a header in the area.

Spain was sharper in the second half after Koke took the field as a substitute for Thiago, and then Lopetegui made a key switch in the 76th minute when he went to three defenders and brought on Aspas for Jordi Alba.

Eight minutes later, the Celta Vigo striker received the ball from Diego Costa in the area and fired a left-footed blast past Tunisian net minder and captain Aymen Mathlouthi.

The goal came as a relief to the Spaniards after they had been stymied for nearly 90 minutes, although some unexpected doubts are now hovering over one of the World Cup favourites.

Even so, Lopetegui took away the positives from the contest.

"It's true the match was very difficult. We didn't have the rhythm we wanted in the first half ... It was a World Cup match, with very little between (the two sides), but in that difficulty we grew against a team that had come into the match after drawing with Portugal (on May 28) and going nine matches without a loss," the head coach said in the post-match press conference.

La Roja's next game will be on June 15 at the World Cup against Cristiano Ronaldo and Portugal, while its other two Group B opponents will be Iran and Morocco.

Tunisia will play its first match in Russia against England in Group G on June 18 and then square off in its final two round-robin games against Belgium and Panama.