Paul Clement has stressed the need for Swansea City to do "good business" to fill the void left by Gylfi Sigurdsson's move to Everton.
Sigurdsson left for Goodison Park on Wednesday in a deal reported to be worth £45million, robbing Swansea of their biggest creative force.
A 4-0 defeat to Manchester United on Saturday highlighted the need for the Welsh club to respond in the transfer market, with Fernando Llorente and Ki Sung-yueng also missing through injury.
And Clement says it is vital that Swansea re-invest the Sigurdsson funds to ensure they are not dragged into another fight for Premier League survival.
"The moment you know Gylfi's going, you know you need to do that," he said.
"And when you haven't got Gylfi in the team, and Llorente, who's injured, and Ki, who finished the season really strongly - when they're all out, we are weaker.
"We've still got a good squad here but absolutely we need more quality players to come in so that we've got a chance of being competitive this year."
Swansea have been linked with Nacer Chadli and former Liberty Stadium favourites Wilfried Bony and Joe Allen.
"It's very fluid the situation at the moment," Clement added. "Texts, e-mails, telephone calls are going back and forward between various parties.
"We hope that by the deadline [we can get something done]. The sooner you can do it the better.
"It's possible it could go later in the window [than next weekend's clash with Crystal Palace], but the necessity is there.
"We need to do some good business."