Premier League top scorer Romelu Lukaku broke another record in Everton's 4-0 win over Hull.
But Koeman stopped short of an outright plea for fans not to jeer their wantaway star.
He had twice gone close from distance before he struck in the first minute of stoppage time after being put through by Valencia. Tottenham's Harry Kane and Lukaku are tied with the most goals in the Premier League this year. "This lad might be able to play at the top", was Keith Briggs's assessment of the teenager's contribution then. If he gets that space he will punish the opposition and that's one of his big qualities.
"Of course, we would like to keep the best players because we think we are in a good direction in this project and you don't sell your best players".
"We need the support, every player who is starting needs support".
Dominic Calvert-Lewin squandered a terrific chance in the reverse fixture in December, but the youngster made no mistake on this occasion as he nudged in Tom Davies' cross to give Everton the lead early on.More news: NCAA Tournament Second Round: No. 3 Florida State vs. No
Relegation-threatened Hull began to gain the upper hand, but the momentum was halted when Tom Huddlestone was sent off for a shin-high challenge on Idrissa Gana Gueye in the 73rd minute.
The result pushes Ronald Koeman's side above Manchester United in sixth while Marco Silva's men find themselves three points adrift in 18th.
"The decision of the referee about the red card was too harsh I believe".
"We know we have played more games and it can be different".
However, a move for Lukaku is not dependent on Costa leaving and Chelsea have marinated that they want their Brazlian-born centre forward to stay, with the prospect of a new deal open to him if he commits beyond the summer. We didn't deserve this.