Spain laboured to a narrow 1-0 victory over Tunisia in an underwhelming World Cup warm-up in Krasnodar on Saturday.
The 2010 champions remain unbeaten under coach Julen Lopetegui, who took over 20 matches ago after the Roja's elimination from Euro 2016 in the last 16 at the hands of Italy.
Iago Aspas scored the only goal against fellow World Cup qualifiers Tunisia seven minutes from the end.
But Lopetegui's search for a consistent centre-forward was made no clearer despite a solid showing from Brazil-born Diego Costa.
The Atletico Madrid forward set up Aspas's winner and was a nuisance throughout for the Africans' defenders. Spain dominated the ball but allowed Tunisia some good scoring chances.
Spain begin their Group B campaign against European champions Portugal on June 15 while Tunisia face England in Group G three days later.