Alex is confident Chelsea can repel the aerial threat of Rory Delap’s long throws to overcome Stoke and reach the FA Cup semi-finals.
Alex is likely to partner captain John Terry in defence as Ricardo Carvalho is nursing a hamstring injury suffered on international duty with Portugal.
The defender will have to deal with the physical presence of City striker Ricardo Fuller, plus the threat of Delap’s long throw.
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But the 27-year-old insists he is ready for the challenge as the FA Cup holders look to reach the last four.
"We have to pay attention to the second ball," Alex said.
"Sometimes it is difficult to win the first one, but you have to win the second.
"You have to play very concentrated and stay compact. Fuller has quality with the ball and he is a strong, strong man, so we have to play strong also and don’t leave any space. We conceded four goals in the last game (to Manchester City), which is no good at home."
Midfielder Joe Cole will be given another chance against Stoke to prove that he can win a place in Fabio Capello’s World Cup squad.
Cole’s contract expires at the end of the season but he has yet to agree new terms, fuelling speculation that his relationship with the club’s owner Roman Abramovich has broken down over his wage demands.
But assistant coach Ray Wilkins insists that Cole will remain at Chelsea.
"We are desperate to keep Joe," said Wilkins. "I know the club are and we as a management group feel the same. He is a very valuable asset to us.
"It is a contractual situation that he and the club I am sure will sort out at a later stage.
"I would not have thought his form has been affected by the contract situation. I just think he has had a long lay off, something like 10 months, and it is never easy to come back.
"I have spoken to Joe on numerous occasions. He is upbeat about his future here. He loves Chelsea. He wants to stay at Chelsea and I am sure that the club and his people will sort the situation out."
Wilkins also remains convinced that Cole can find a way back into Capello’s plans.
"We are quite confident that Joe can get his form back and get into that 23 for South Africa," added Wilkins.
"I am sure if he performs to the ability we know Joe has, then Fabio will take him.
"But as Fabio said, he has not been too impressed with Joe’s form over the last couple of months, that’s why he did not make the final 23 for the Egypt game.
"He will give England something slightly different. He can play on both sides of the pitch and in different formations."
Chelsea will also have to cope for the rest of the season without the services of right-back Jose Bosingwa.
He requires a further operation on his damaged knee and will miss the remainder of the season and the World Cup finals with Portugal.
Bosingwa, 27, underwent surgery after initially sustaining the injury against Aston Villa in October.