Mauricio Pellegrino says Southampton did everything in their power to bring Theo Walcott back to the club.
Walcott, 28, sealed a £20m move to Everton on Wednesday despite Southampton’s attempts to lure him back to St Mary’s, where the forward began his career in 2005.
Pellegrino says the club must admit defeat on the matter and concentrate their efforts on bringing in alternative targets before the January window closes.
Speaking ahead of Sunday’s game against Tottenham, he said: “That is part of the market. The market has got offers and demands.
“I think we did everything to try to bring this [player] here but we have to accept that. It’s part of our job.
“When you are in negotiations they are about two parts and we can do nothing.
“Obviously the money is part of the negotiations but I don’t know the reason. We have got in our club the concern to try and bring a couple of targets.
“We have got another option and we have to continue with our job.
“Sometimes we expect this and we have to be prepared for this because it’s part of the market.”
Sky Sports reports Southampton remain in talks with Monaco for striker Guido Carrillo and are hopeful of concluding a deal.
Pellegrino suggested the 26-year-old is on Southampton’s radar but insists he does not want to discuss players who are contracted to other clubs.
“He’s a player I know and the club know,” he said.
“But I will not talk about someone else who is not here. The player is either yours 100% or nothing. One small detail can change the negotiation.
“If we bring people here it is because we feel they will improve the squad.”