Low marked Gosens out for special praise in his post-match media conference and hopes there is plenty more to come from the 26-year-old.
"I don't know if it was the game of a lifetime for him, maybe he still has to play that," Low said.
"But it was an amazing performance from him. He worked very hard and on top of that he was a constant threat up front as well.
"That is exactly what we needed today."
Germany's first win of the tournament helped it move up to second in Group F, one point behind leader France, which was stunned by Hungary and a 1-1 draw in Budapest.
A draw in its final group game against Hungary on Thursday (AEST) should be enough to see Germany progress to the knockout stages, but Low did not think the victory was a sign of how far his side can progress in the competition.
"It doesn't have anything to do with initiating something," he said. "It gives you some satisfaction but we never had any doubts after losing to the world champions, we knew we could do better.
"At a tournament you know how it goes, step by step. The next step will be Hungary, which will be hard as they park the bus in defence.
"Overall it was a strong performance against a technically good Portuguese team who were strong on the counter-attack.
"Especially after going behind we showed a great team spirit, we didn't lose control, we were dynamic and energetic and created a lot of opportunities.
"We managed to be a threat to the defence and overall this victory is well deserved."
Cristiano Ronaldo had put Portugal ahead early on with a strike that took him level with German Miroslav Klose as the European player to have scored the most combined goals (19) across the FIFA World Cup and European championship.
Low's side stormed back before half-time, however, courtesy of two own goals in the space of four minutes from Ruben Dias – forced by a Gosens cross – and Raphael Guerreiro.
Gosens, who had earlier seen an effort ruled out for offside, then teed up Kai Havertz for a third shortly after the interval before eventually getting in on the act himself, heading home Joshua Kimmich's cross at the back post.
Diogo Jota pulled one back for Fernando Santos's men, but a late comeback failed to materialise as Germany sealed its first win of the tournament in style.
Portugal, meanwhile, became the first reigning champion in European championship history to concede four goals in a single match in the competition.
Boss Santos accepted full responsibility for the result and said it is up to him to turn things around for the final group game against France on Thursday (AEST).
"Whether we progress or not is up to us and we have to respond to this," he said.
"The manager is to blame for the result. If we look at individual players it would be shooting ourselves in the foot. Now I have to talk to the players and understand why we couldn't do what we planned to do.
"I am responsible for this, I don't want to mention players by name as we need to solve this as a team and think about France.
"France play differently and we need to change the things we did which were not that good."