Martinez's side play host to Kiev in the first leg of the last 16 tie on Thursday, having comfortably seen off Young Boys 7-2 on aggregate in the previous round.
However, their league form continues to be a cause for concern, with a run of one win in 12 matches seeing them slip to 14th, six points above the relegation zone.
"It is very much taking each game in isolation," Martinez said on Wednesday.
"We know the severity of our situation in the league. The severity of the situation in the league is something different to what we'll face tomorrow night.
"It's been difficult to get two good results together. We know our situation in the league - but our focus now is Kiev.
"Some of the individuals Kiev have are very special. There are many players in their team that are of the highest level.
"Playing at home is an advantage we need to use. They are going to try and win the game at Goodison.
"Teams who come to Goodison are very wary of what we can do. We have not been able to perform.
"The next two weeks are going to be important. The squad are mentally ready for what lies ahead."
Martinez also confirmed that the quintet of Leighton Baines, Bryan Oviedo, Tony Hibbert, Steven Pienaar and Aiden McGeady would all miss the game, while Leon Osman and John Stones are to be monitored.
