Then he had to wait a frustrating 84 minutes before he finally saw his side grab the goal they needed to make it a winning start to his reign in the Hoops hotseat.
His decision to pitch 21-year-old Callum McGregor into the Champions League qualifying tie against KR Reykjavik ahead of in-form Finn Teemu Pukki - and to allow him to remain there for the entire match - paid off big style.
The kid, who spent last season on loan at Notts County, cut in from the right wing and, with the aid of a slight deflection, found the net.
The huge relief among the Celtic travelling party was tangible.
The last thing Deila needed was a false start to his time in charge, especially against a team of part-timers rated at 6-1 to win this tie on their own patch.
Deila would have preferred a healthier lead to take to the second leg at Murrayfield on Tuesday.
But, given just how heavy weather they made last night's game, nothing will be taken for granted.
Deila will trust that his players will all strip fitter and sharper for the competitive outing they have now had.
They will need to, because KR will arrive at the Edinburgh home of Scottish rugby ready to turn any repeat of the shortcomings by the Hoops into a shock result.
Deila learned a great deal about his players, and also about venting his feelings before the whistle blows.
He made no attempt to hide his disgust for the fact Celtic have to enter the qualifying process at such an early stage.
Better to focus on what you can control. And, in this instance, that's the results of the games you are obliged to play - even if they do come before the Glasgow Fair.
Twelve months ago - the first time they had to enter the competition at the second qualifying round - Celtic disposed of Cliftonville, not conceding a goal in either leg and scoring five themselves.
Perhaps Deila had sneaked a peak at those results, which would explain why he was happy to pronounce before kick off in Iceland that he believed his side "had a very good chance of getting a good result," against the part-timers from Reykjavik.
The positive message was relayed to the players, who were eager to get the new manager's tenure off to a positive start in front of just 1500 fans at the Junior-park-like KR Vollur Stadium.
He elected to go with his World Cup returnees, Fraser Forster, Emilio Izaguirre and Efe Ambrose, despite the fact the first two have each played only one warm-up game and the Nigerian not even that.
More of a surprise - and, to the player in question, undoubtedly a disappointment - was that there was no place for in-form Pukki.
His goal-fest in Austria did earn him a place on the bench, but he would much rather have been out there alongside, or in place of, Anthony Stokes or Leigh Griffiths.
Truth be told, despite what was at stake - elimination from Europe entirely if you get knocked out at this stage - this game had the feel of another in the series of pre-season warm up matches.
Perhaps it was the small surroundings, the standard of the opposition, the sticky pitch, the timing of the tie, or a combination of all four.
Whatever the reason, there was a serious lack of the intensity and tempo required.
Every misplaced pass or moment of sloppiness - and Ambrose was particularly negligent - gave KR a little bit more belief that they could cause an upset.
The fact they got to the interval having restricted Celtic to very few genuine scoring chances - the best of which was a Commons volley from 22 yards which rattled the crossbar after just nine minutes of what had been, to that point, one-way traffic - saw the compact home team's satisfaction matched by Celtic's frustration.
KR's only real look at Forster had come half-way through the half, Englishman Gary Martin latching onto a poor headed clearance by Izaguirre, but his countryman was more than capable of swallowing up his low drive from distance.
Deila's half-time team talk would have made interesting listening. The Norwegian had remained calm and composed on the sideline, but he could not have been satisfied with what his players had produced.
The call to step up the pace was answered almost from the restart, and Commons' link-up play with Stokes put last season's top scorer into excellent scoring positions, all of which he spurned.
A few more games under his belt, and these are the sort of chances Commons will convert with ease, as he did 32 times last term. But that is precisely why these ultra-early European ties are so tricky.
Griffiths, too, will come on for the outing, and will hope he can get the chance to play through the centre rather than on the right wing, where he was billeted for this match.
Even from there, he showed his threat, cutting inside on to his left foot and hammering a shot off the under-side of the bar before it was cleared by a tiring KR defence.
It was something of a surprise, therefore, to see Griffiths join Stokes in leaving theaction with just 16 minutes to go, replaced by Derk Boerrigter and Pukki.
Pukki had a golden chance to announce his arrival within 60 seconds.
Commons' shot was pushed out by Magnusson, who did well to block McGregor's attempt to convert the rebound.
The ball ran to Pukki, but he pushed it too wide before wheeling and sending his shot into the side net.
It looked like being the story of Celtic's night - until McGregor rode to the rescue with his late winner.
KR REYKJAVIK: Magnusson; Haukur Hauksson, Josepsson, Gretar Sigurdsson, Gudmundur Gunnarsson; Atlason (Ormarsson 88), Saevarsson, Baldur Sigurdsson, Lorenzo; Finnbogason, Martin Ragnarsson 81). Subs: Jensson, Egil Jonsson, Gunnar Thor Gunnarsson, Hroar Sigurdsson, Zato.
CELTIC: Forster; Lustig, van Dijk, Ambrose, Izaguirre; Johansen, Mulgrew; Commons; Griffiths (Boerrigter 74), Stokes (Pukki 74), McGregor. Subs: Zaluska, Matthews, Kayal, O'Connell, Henderson.
Referee: Andreas Pappas (Greece).