Mebrahtu sealed the Wanderers' 1-0 win over Brisbane Roar in the midweek FFA Cup round of 32 tie at Penrith with a well-taken goal midway in the second half.
Mebrahtu, 24, made the most of his first start for the Wanderers since joining the club from then Melbourne Heart in February 2014.
He has played very little for the Wanderers after suffering a serious knee injury in a match against Perth Glory a month later.
"My faith in God was most probably the strongest factor which made me determined to come back stronger and fitter," Mebrahtu said.
"When you have a long-term injury and you see players progressing in their careers, there is always doubt in the back of your head.
"But you have to put that aside and believe in yourself.
"You have to put in the good work and thankfully tonight it paid off."
Mebrahtu said he now was ready to put his misfortunes behind him and concentrate on the challenges ahead.
"Injuries come with the sport, to be honest," Mebrahtu said.
"I have been unlucky but touch wood all the hard work the team and I have put in will be rewarding in the end."
Sudan-born Mebrahtu was only too happy to relive the moment that could prove to be the launching pad of a successful stint with his new club.
"It was a really good build-up from the boys. I was on the left flank and I saw Romeo (Castelen) control the ball," he said.
"He had his back towards goal and he laid the ball off to me. I took a touch around the defender and was able to put it in the bottom corner."
Mehrahtu can expect a few more starts this season after a highly positive game against Brisbane but he acknowledged that "one game does not make a season".
Wanderers coach Tony Popovic sounded a warning to the media not to get carried away with its assessment of a player who is not in peak physical and match condition.
"It's one step at a time with Golgol," Popovic said.
"In the second half he did well but in the first he was very tired.
"I'd like to check the last time he played 75 minutes, I'd say it's almost two years.
"So we can't say that all of a sudden he's now a starter.
"We have to look after the boy as we have for the last 12 months and we want to help him build a foundation so he can have a good career for the next 10 years.
"He has played six full games in the last five years and that is not a player who can play every week. So we have to make sure the media keeps things in perspective."
Mebrahtu said Popovic had been the major factor in his decision to trade Heart for the Wanderers.
"The coach, very simply, was the main reason I joined the club," Mebrahtu said.
"I had opportunities to go to other A-League clubs and I chose to come here because of the success the club was having and the impact the coach was having on players.
"Injury-hit players like Matt Spiranovic and Tomi Juric came to this club and rebuilt their careers and moved on to better things.
"I looked at what he was doing with players and this was very attractive to me."
