Ernesto Valverde believes Inaki Williams will become a "great player" for Athletic Bilbao and has praised the young forward for his versatility.
Williams, who has represented Spain at under-21 level, scored twice in the first half for Athletic in their 3-1 win over Real Betis on Sunday.
The 21-year-old has become a regular in Valverde's starting XI in recent weeks, with his coach using him out wide to add pace to the attack.
"He came to play as striker, but we have seen the possibility that he can play as winger," said Valverde.
"He is a player who has self-confidence, can score a goal and is very fast.
"He will be a great player."
Williams and the rest of the Athletic squad play Partizan in Europa League action on Thursday.
The teams sit on six points in Group L going into the game, though the Spanish side are top of the table after a 2-0 victory in the reverse fixture in Serbia.
Valverde is expecting a similar match to the one played out in Belgrade as his side look to record a fourth successive win in all competitions.
"We have two of the three remaining games at San Mames, but all the teams have something to say. Anything can happen," he said.
"I think the game will be similar to the match of Belgrade. They play away and will try to make counter-attacks. In Belgrade they tried it, but we managed to play our game."
