The Chile international, who played under Guardiola at Barcelona, has just over a year left on his deal at the Emirates Stadium.

That has led to speculation that the Gunners might have to cash in on the player this summer to avoid losing him on a free transfer.

City are one of the clubs that have been linked with the 28-year-old and while Guardiola has never indicated any interest, he does think rival clubs will be watching developments closely.

He said: "Put it that Kevin De Bruyne had one year left on his contract, see how many teams would have him. Normally the big players have two, three years [on a] contract.

"All the clubs in the summertime are going to try to improve. How do you improve the teams? Better players. Of course [people will watch] all the players around the world. Alexis is one of them. They are going to know his situation.''

Sanchez never truly established himself at the Nou Camp but Guardiola points out that all players look inferior at Barca when compared to Messi.

"Messi creates that,'' said Guardiola, whose side face Sanchez and Arsenal in Sunday's FA Cup semifinal at Wembley.

"All players that go there and start training with them realise immediately they cannot compete, they will always be below [Messi].

"Even the big players that believe they are top, they go there and they understand. Messi is unique.

"But Alexis is just one step below, a fantastic player. I am so happy how he is playing there, especially this year, scoring goals and assists and so on.

"The quality means when Arsenal were tied -- free kick, goal. Good players make these kind of things, the difference. Alexis is a player of that level.''

Alexis Sanchez has only one year remaining on his contract at Arsenal.

The FA Cup now represents City's only hope of silverware this season after failing to mount a serious Premier League title challenge and crashing out of the Champions League at the round-of-16 stage.

It has been a tough first season at the club for Guardiola, who arrived to much fanfare after his past successes with Barcelona and Bayern Munich.

The Spaniard, who has never previously finished a campaign empty-handed as a manager, believes he will learn much from the experience.

He said: "I am a better manager not because I am in the Premier League or in English football, but because I have lost more games than in my recent past. When you lose more you learn more. I improve myself.

"During the part of the season when we went four or five games without winning I went home and said: 'Pep now you have to see how good you are as a manager, now is the moment to show yourself.'

"I know if we don't win titles I will be criticised and the season will not be good. The expectation was so high before I arrived but I have to accept and deal with that.

"I came here to prove myself, that I am able. I expect to do that in a hurry, quick, but football is like this. Sometimes it takes more time.''