Moyes, though, felt Sippel could have changed the course of the game at the Stade Maurice Dufrasne if he had dismissed Liege skipper Steven Defour.
Defour was shown a yellow card for dissent after protesting too vehemently about a decision that went against his side.
Defour was seen screaming in the face of Sippel, and almost coming into bodily contact with the official, but as far as Moyes was concerned he only escaped with a caution.
The Scot also felt Sippel failed to spot a clear foul later in the first half which could have led to a second booking, and potentially a sending off.
Moyes reflected: "I am thinking about the referee's decision not to send off Defour, which I thought on two occasions was so poor.
"In England you are not allowed to do what he did to referees. Maybe in Europe it's different.
"Then there was a professional foul after it, which was maybe another yellow card.
"I think the crowd were very good for Standard. They influenced the referee - they did a very good job.
"If he (Defour) had been sent off it would have made a difference because he had the shot that led to their first goal.
"We were playing well against 11, so against 10 we would have had more space.
"I think it (a dismissal) would have made a big difference to the tie at that time."
Defour's 22nd-minute shot was superbly turned away by a full-stretch Tim Howard, but Milan Jovanovic was quickly on the rebound, with his cross to the far post turned home by Axel Witsel.
But still requiring a second goal, the Merseysiders again left themselves open at the back in the 78th minute, culminating in Leighton Baines bundling over Jovanovic inside the area.
The Serbian then picked himself up to beat Howard from the spot and add to the early season woes for Moyes, whose side are also yet to win at Goodison Park this season.