Ole Gunnar Solskjaer believes Manchester United are "in good shape" but must still develop a killer instinct following a lean run in front of goal.
United travel to West Ham on Sunday in search of a third successive victory in all competitions.
Mason Greenwood's second-half effort saw off Astana in the Europa League on Thursday and added to last weekend's narrow Premier League win over Leicester City.
While secure at the back, Solskjaer's men have failed to score more than a solitary goal in any of their five games since the 4-0 opening-weekend triumph over Chelsea.
Starting striker Marcus Rashford netted twice in that match but has only added a single successful spot-kick to his tally ahead of the trip to the London Stadium.
"Winning gives confidence and clean sheets give the defenders confidence and we just need to be more clinical in front of goal," Solskjaer told his club's website.
"We're in good shape and we've prepared well for this game.
"We had one eye on Astana but the other eye was on West Ham so we should be ready for it."
West Ham were themselves held goalless in their last outing, a 0-0 draw at Aston Villa, but only after losing Arthur Masuaku to a red card in the 67th minute.
The hard-earned away result moved the Hammers level with United on eight points from five games.
"I think they're looking strong," Solskjaer said of Manuel Pellegrini's side.
"Of course they have some quality players and their centre-forward [Sebastian] Haller has come good for them.
"It's good to see [Andriy] Yarmolenko and [Manuel] Lanzini back fit because I know all about knee injuries.
"We played them [at Old Trafford] towards the end of last season and we were lucky to beat them, so we know it's going to be a tough game."