Emiliano Martinez acknowledged he has work to do with Chelsea's defence to help them stop conceding so many goals.

Chelsea signed Martinez from Aston Villa for a reported £7.5 million and he made his debut in a 4-3 victory over Brighton at Stamford Bridge on Saturday.

Xabi Alonso's side stormed into a three-goal lead thanks to Romeo Lavia, Pedro Neto and Joao Pedro, but Malick Yalcouye pulled one back before Joao Pedro's own goal set up a tense final 30 minutes.

Cole Palmer gave Chelsea a two-goal cushion, but their defence was breached again before the final whistle, with Pascal Gross' header meaning the Blues have conceded five goals in their two Premier League games under Alonso.

"A win is a win. I know it wasn't a perfect game. But in the end, winning and moving on is what we need. We've got 36 games left, and it's one week after another," Martinez told Sky Sports.

"I am here for a reason. The front three is amazing. When we go forward, we can hurt teams. We had a lot of chances to finish the game. Cole Palmer and Joao Pedro had chances to kill the game. At the back, we need to bring the goals down.

"I know how big this club is and what we want to achieve this season. I came here to help.

"I had an amazing seven years at Aston Villa. I have come here to challenge and to try and win the Premier League.

"I trained only one day with the team. The guys have treated me really well in the last day or two. I know the talent we have up front. I try to bring that solidity in the back."

Brighton enjoyed a 74.4% share of possession – the highest by any side in a Premier League game against Chelsea – and head coach Fabian Hurzeler was frustrated not to have left Stamford Bridge with at least a point.

"It's a frustrating result. Although we showed a good performance, we weren't brilliant at the basics," Hurzeler told beIN SPORTS.

"We really had an opportunity to take something away from here. We dominated the game, we had the ball, we created plenty of chances.

"In certain moments, we could've done better, so that's something we have to improve. But I'm proud of the boys.

"In the second half, we showed the belief that we were there to get something. Overall, it was a frustrating afternoon, but we will take plenty of positives away."