Antonio Rudiger is frustrated that his side didn't finish off Arsenal when they had the chance in their International Champions Cup match in Dublin, as the Gunners won on penalties after a late Alexandre Lacazette equaliser.
The Germany international had opened the scoring in the fifth minute but saw his side miss a hat full of chances, including an Alvaro Morata penalty, as they dominated the first half.
Arsenal grew in confidence in the second half and the 1-1 draw saw the game head to penalties. Petr Cech saved from Ruben Loftus-Cheek and Alex Iwobi scored the decisive penalty. Rudiger thinks that Chelsea still have a lot of improving to do under their new manager Maurizio Sarri.
"I think in the first half, we started well. We started very good," Rudiger told Goal at the Aviva Stadium. "We scored early and that was very good, we had also could have scored more in the first half. In the end of the first half, we were a bit sloppy.
"We gave away possession to Arsenal and yes, we continued like that in the second half. The final pass was missing, these are things that we need to work on very quickly. I think the second half, it was an open game but to concede like this in the last minute. No, we have to win this."
Sarri described the match against Arsenal as his "most important pre-season game" ahead of kick-off, as Manchester City are up next in the Community Shield on Sunday.
Rudiger is likely to start alongside David Luiz once again to face the Premier League champions at Wembley and he hopes to continue being more of a goal threat into the new season.
"I was happy to score," he said. "This is my aim, I always try to do that and I hope to get better [at scoring]."