"It was not an easy game, a lot of new players is not an excuse, we have to win, we need wins because we are mid-table, we want to be at the top," Kepa told the official Chelsea website after a 0-0 draw with Fulham.
"It's not a long time to do it, [but] we have to do it in the middle of [season]," he added about the need for the newcomers to adapt.
"Like Enzo, like Noni, they showed their quality and what they can add to the team. It's time to build and go again next week.
"We can't wait to be back in the Champions League. It's a big game against West Ham next week. We have all of the week to prepare for it and we'll go there for a win, for three points because we need it."
Kepa has kept three clean sheets in a row, but the Blues only managed to score once in those three games, suggesting the problems lie further afield.
Chelsea had three January signings in the starting lineup, with two more newcomers coming on from the bench.
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Graham Potter claims he's 'confident' Chelsea can push for top-4 finish
"I'm confident with the potential we have. I'm confident with the ability we have within the group," Graham Potter said when asked if he believed that Chelsea could finish in the top four this season.
"What we need to do now is gel the team," he added. "That's the challenge, that's what we have to do.
"There's still more football to play, but at the same time I don't want to worry about what we're going to do in four, five months' time. I need to focus on the next day, the training session and the next game."
After the 0-0 draw with Fulham, Chelsea are ninth in the Premier League table, nine points behind fourth-placed Man United who have a game in hand.
Missing out on the Champions League will be a heavy blow to Chelsea who have spent over €600m on transfers and rely on the income from the European competitions.
