Arsenal head into Tuesday’s League Cup semi-final second leg with a 3-2 advantage, but manager Mikel Arteta is under no illusions about the challenge posed by an in-form Chelsea side.

Since losing to Arsenal in the first leg last month, Liam Rosenior’s Chelsea have won all five of their matches, securing direct qualification for the Champions League round of 16 after finishing sixth in the European competition’s league stage and climbing to fifth in the Premier League.

“Tomorrow we have the home advantage, but we have a lot to do to beat a really good Chelsea side,” Arteta told reporters on Monday. “I think Liam is doing an incredible job… we need to be very concrete to win it.”

Chelsea manager Rosenior, unbeaten in his five matches since taking charge (aside from the first-leg loss), acknowledged Arsenal’s advantage but insisted his team would fight until the end.

“They’re a goal up and at home. They’ll expect to go through. We need to take it as far as we can,” he said.

Arsenal, buoyed by a 4-0 Premier League victory at Leeds United, face a fresh injury setback with midfielder Mikel Merino set for surgery on a fractured foot sustained during the loss to Manchester United.

“He is a big player for us. It’s a big blow… it’s a very rare injury. We’ll have to keep monitoring it,” Arteta said.

With the winter transfer window closing on Monday, Arteta confirmed the club would explore options to fill the void left by Merino.

“When you lose a big player in the squad, you need to do everything you can to see if someone is available. If not, we move on,” the manager said. “The news of Mikel was very surprising. My day will be a bit busier than usual.”