The Europa League group stage campaign kicks off for the Toffees at Italian side Atalanta. Following the 3-0 defeat to Spurs at Goodison Park on Saturday, Koeman will be hoping for an immediate response from his men.
'It is all about the way of thinking of the responsible people in the club', Koeman said. 'I am the manager and I take it really seriously, we showed that already in the qualification rounds, to reach the group stage. It will not be different tomorrow'.
Everton want to get their European campaign started with a win in Italy, after suffering a heavy home defeat on Saturday and with their Premier League trip to Old Trafford on Sunday.
Wayne Rooney travelled with the rest of the squad to Atalanta but is likely to be benched as he is due to appear in court on September 18 after being charged with drink driving.
Sandro Ramirez and Dominic Calvert-Lewin could lead the line for the Toffees at the Mapei Stadium, while James McCarthy, Yannick Bolasie, Seamus Coleman, Ramiro Funes Mori and Ross Barkley will be out with long-term injuries.
The Italians will be taking part in European competition for the first time in 26 years after finishing fourth last season above the likes of Inter, Milan or Lazio.
The hosts could line up a 3-4-3 formation as they search for their first continental win since 1991. Former Middlesbrough midfielder Marten De Roon could start tonight.
Atalanta v Everton potential lineups:
Atalanta: Berisha; Masiello, Caldara, Toloi; Gosens, De Roon, Cristante, Castagne; Gomez, Cornelius, Ilicic.
Everton: Pickford; Baines, Williams, Keane, Holgate; Gueye, Davies, Sigurdsson, Klaassen; Sandro, Calvert-Lewin.