"The fact it came from a set piece was doubly disappointing. They got the goals when it mattered and ran out comfortable winners.
"We have to keep going and try to find the magic formula.
"We get Kenny Deuchar back from his loan spell at St Johnstone on Monday and maybe he is the player to start scoring for us.
"Results elsewhere did not go for us but we won't give up because we knew from day one it would be tough. We have to keep believing we can reduce that gap at the bottom."
Irons said Gretna would present no barrier to Rangers' bid to convince the authorities to postpone Sunday's televised game at Fir Park ahead of Gers' crucial Euro clash with Lyon.
He added: "As soon as Stuttgart scored that winner I thought Rangers would be looking for a postponement.
"We would help any Scottish club because it helps the co-efficient. And we'd happily aid Celtic, Aberdeen, Hearts or anyone in a similar situation."