The Parkhead side failed to qualify for the Champions League after a dispiriting 1-0 defeat at home to Maribor of Slovenia on Tuesday night but the Celtic board will support the manager and follow their long-term strategy despite protests from about 200 fans outside the ground.
Celtic now lose out on the £15m-plus revenue that comes with the group stages of the Champions League with the Europa League only offering a comparatively paltry £4m but Deila last night said he was looking to recruit a further two players after Wakaso Mubarak, the Ghanaian internationalist, signed a one-year loan deal with the option to buy from Rubin Kazan. A deal for Sporting Gijon striker Stefan Scepovic has stalled with Celtic sources blaming work permit problems.
Deila, though, last night insisted the club were hopeful of signing two players before the window closes on Monday. Further reinforcements will be brought in during the January transfer window as the 38-year-old Norwegian seeks players who can fit in with his strategy.
"The club want to invest in the team but I have been here a short time and it's important that we do things in a good way so we know what we are doing. It's difficult to get the quality of players that I know the fans want to get and that I want to get as well," he said.
"But I think now, in this window, we will have a signing or two more. In the coming one in January as well, we need now to build up the team so that we can stand in a whole other situation next year. Players want to play for Celtic, and those who can develop and take a new step in their career, they are the ones who want to play here."
Deila is aware he has only two transfer windows - with only days remaining in the first - to forge a team capable of coming through the Champions League qualifying campaign next season should, as expected, Celtic win the SPFL Premiership again.
His major priority is a striker with strength and pace who will hold a crucial place in the 4-3-3 set-up he prefers. Cameron Jerome, the 28-year-old Englishman, has rejected Celtic for Norwich City and Scepovic may be bound for PSV Eindhoven. However, Celtic have identified other targets.
Deila remained brutally frank about Celtic's failure to progress against Maribor after gaining a reprieve having lost 6-1 on aggregate to Legia Warsaw but been given a reprieve because the Polish side fielded an ineligible player. "We didn't deserve to be in the Champions League and we have to start building now," he said. "We're not good enough and now it's the Europa League and we are going to do everything we can now to achieve things in that cup."
The draw for that competition is tomorrow night and the squad is bolstered by the arrival of Wakaso who may be included for the match against Dundee on Sunday.
The winger has 19 Ghanaian caps and featured against both Germany and Portugal in this summer's World Cup in Brazil.