The France Under-21 striker made his Arsenal debut on Sunday after just a few days of training with his new team-mates.
Sanogo almost opened his account for the Club inside the first minute and showed glimpses of his raw talent before making way for Olivier Giroud in the second half.
There's a lot of competition for that position. I think he showed his qualities in patches today definitelyTheo Walcott
"He's a strong boy," noted Walcott. "He's only had a couple of training sessions with us. I've only trained with him a couple of times.
"He's a nice lad and I think he'll do very well for us. There's a lot of competition for that position. I think he showed his qualities in patches today definitely."
While Sanogo was denied a debut goal, Walcott did find the net in peculiar circumstances when his left-wing cross eluded everyone to creep in at the far post.
"You see a lot of them every year," he said. "You just put them into the area, everyone gets confused about where it's going to go, the goalkeeper doesn't know whether to commit or not and it snuck in. It was nice.
"It was disappointing in the end [to lose the game]," added Walcott. "I felt like we dropped off. But they showed their class with Wesley Sneijder and Didier [Drogba] coming on at half-time. It showed a bit of a different presence for Galatasaray.
"I think you've got to take a lot of positives out of the game. It's good fitness work as well and that's the whole point of it all. Come the start of the season, we'll be ready.
"We've got another couple of weeks of training before the start of the season and everyone will be sharp - trust me. It's a big wait."Copyright 2017 The Arsenal Football Club plc. Permission to use quotations from this article is granted subject to appropriate credit being given to www.arsenal.com as the source