Spaniard Roberto, signed from Espanyol in the summer, conceded four times in the embarrassing midweek Carabao Cup loss at Sky Bet League One Oxford and endured some shaky moments on the south coast, particularly with his kicking.

Chilean coach Pellegrini insists he has no concerns about the capabilities of the well-travelled former Benfica, Olympiacos and Malaga keeper.

"Roberto is a great goalkeeper. He has a brilliant career in a lot of different countries," said Pellegrini.

"I know him a lot, that's why he came here.

"Now he has the chances because (before) it was difficult for him to play because of the performances Lukasz was having in every game.

"But I trust him a lot and I'm sure he will replace Lukasz in the way he knows how to do it."

Andriy Yarmolenko and Aaron Cresswell were on target for the second successive week as the high-flying Hammers made it six top-flight games without defeat.

Ukrainian winger Yarmolenko has now scored three times this season after missing most of the 2018-19 campaign with a torn Achilles.

Pellegrini believes the former Borussia Dortmund player is reaping the rewards of his desire and determination to return to first-team action.

"Andriy's a special player. I think that we brought him here because he's a very technical midfielder, but in his complete career he always adds goals," said Pellegrini.

"He was very unlucky last season.

"In his best moment he had that injury – his Achilles tendon – but he returned working very hard, so I am very happy for him with his performances because he is not only scoring, he doesn't lose any balls during the game and he's always working very hard."

Bournemouth, who came from a goal down to lead thanks to strikes from Joshua King and Callum Wilson, welcomed back captain Simon Francis as a late substitute for his first league appearance since suffering knee ligament damage on Boxing Day.

Cherries manager Eddie Howe believes the recovery of 34-year-old Francis is a major boost and also feels his team have plenty more to offer, despite their strong start to the season,

"He is a big player for us and obviously to have him back in the group is a huge moment," Howe said of Francis.

"I still don't think we've hit our best efforts yet. In terms of performance, I think we've got more to come.

"Some really good signs, but a lot of room to improve."