Slaven Bilic believes West Ham can start turning around their Premier League form after the confidence boost of a Carabao Cup victory.Diafra Sakho and Andre Ayew struck just before half-time as West Ham ran out comfortable 2-0 winners at Cheltenham to reach round three.Hammers boss Bilic had the look of a relieved man after avoiding a cup upset on the back of conceding seven goals in opening Premier League defeats to Manchester United and Southampton."Nothing gives you confidence like a win so this is very important," Bilic said."Like every defeat harms your confidence, every win, every goal and every clean sheet gives you confidence."So a little bit of this is going to help us in preparation for the game against Newcastle on Saturday."It wasn't a friendly game, it was a cup game, and we wanted to go through because we are ambitious in the cup competitions."There is a huge difference in class, of course. We are Premier League, they are fourth tier."Every year, every round, there are a couple of surprises - so we knew it would be a difficult game."But we also knew if we were concentrated we could make it easier for us."Sakho eased any West Ham anxiety when he opened the scoring five minutes before half-time.It was Sakho's first goal since he scored in a 1-1 draw at Manchester United last November, the Senegal striker having had a cruel time with injuries since."He didn't score because he didn't play," Bilic said."We know his strengths but the problem for him last season was that he played only four games."So hopefully he's going to stay fit long-term, that would be a big boost for us."Cheltenham, of Sky Bet League Two, battled valiantly in the second half and Mohamed Eisa and Dan Holman had opportunities to reduce the deficit."I was proud of the boys' performance, apart from a few minutes at the end of the first half we matched them," Robins boss Gary Johnson said."I thought we played with a real energy and passed it well, but they had the Premier League finishes and we didn't."The aim was to keep it at 0-0 and see what would happen, but even at 2-0 we created some good chances."We stayed in the game, but I was thinking if we could get one then we would really be in it."We gave it a go, but unfortunately it wasn't to be."