Frank Lampard lamented the amount of errors Chelsea made during their 3-3 draw against West Brom.
Chelsea trailed 3-0 at half-time, featuring mistakes from Marcos Alonso and Thiago Silva.
"You can do as many meetings as you want -- if you're going to make those mistakes, you're going to give yourself a mountain to climb ... it is a big lesson for us. We will get a lot better. We're still finding our way with new players and a lack of pre-season. Today is part of the process of getting better," said Lampard after the match.
Chelsea currently have four points from their opening three matches.
Lampard added that Chelsea won't hit their stride until after the international break.
"In terms of team fitness, it won't be until after the international break [in October] that I expect to see us up to our real level, especially in terms of on the ball, because we haven't had time to work on that yet."