The Hoops boss had handed a host of first team stars a rest following their Europa League exertions away to Salzburg on Thursday night but his decision came back to haunt him when John Sutton fired Motherwell into a 19th minute lead.
Deila brought captain Scott Brown and Commons off the bench at the break and the pair combined to haul Celtic back on level terms as Brown won a 68th minute penalty that Commons converted.
The result leaves Celtic in fourth place, five points behind leaders Dundee United who thrashed rivals Dundee 4-1 earlier on Sunday, albeit the Glasgow giants have a game in hand over their rivals.
It has been a stuttering start to the season for the defending Scottish champions and Deila, who celebrated his 39th birthday on Sunday, has just five wins from his first 13 matches in charge at Celtic Park.
The Norwegian admits his side need to start winning if they are to clinch the title and is looking for more from his squad players.
"We look at the table all the time
We want to win the league so we can't have many days like this," Deila said.
"We wanted to win the match and I think we deserved it in the end but we made it so difficult for ourselves as the first half was so poor.
"I think in the second half we had two good subs coming on who brought energy into the game and I think we played quite well but everyone in the squad needs to improve as we can't rely on one or two players.
"We need to build leaders out on the pitch when Scott and Kris are not out there
That is good learning experience but I'm very disappointed with the performance in the first half
The second half was good
The first half was the opposite.
"We have brought in some young players and some of them haven't played so much in the clubs they've come from so we have to be reasonable with them and understand that they can't just come in and be kings on the pitch."
It is not the first time Deila has come in for criticism for his squad rotation
The Celtic manager made 10 changes for his side's loss to Inverness earlier in the season before a European game but Deila says the six changes he made against Motherwell were out of necessity.
"I don't want to rotate very much
That's not what I want but that's what we need as we have many players out with injuries and there are new players coming in as well," Deila said.
"There are things that we still need to do and we have see this as a bigger picture than just the one game.
"If we are going to beat Hearts in the League Cup on Wednesday we need 90 minutes like the way we played in the second half as they are a good team."
Elsewhere, Dundee's unbeaten start to the season came to an emphatic end with a 4-1 defeat at home to city rivals United.
Mario Bilate's penalty gave United a 25th minute lead before Ryan Dow doubled their advantage just after the break
Headers from Callum Morris and Keith Watson completed the scoring for United.
Things got worse for the home side when Thomas Konrad was sent off in the 90th minute for a second bookable offence before Greg Stewart scored a consolation goal in the third minute of stoppage time
However, that wasn't enough to stop United moving to the top of the table on goal difference from Inverness Caledonian Thistle.
Source : AFP
Source: AFP