But the former Scotland winger has warned the Buddies youngster and his team-mates to remember the scare the Irn-Bru Second Division side gave Rangers earlier this season.
Teale has been impressed with the impact the 18-year-old has made since forcing his way into Danny Lennon's team earlier on this month.
The midfielder made his first start for the Saints in their 3-1 win over bottom-placed Dundee in an SPL game in Paisley last Saturday.
And on Tuesday night he helped St Mirren grind out a 0-0 draw with Ross County at Victoria Park.
Teale said: "John is working hard in training and is doing well as a result.
"He is still just a young boy, only 18, but he has certainly deserved his chance in the first team.
"John is in the team on merit. He has started our last two games against Dundee and County and has helped us take four points.
"He is a confident boy; he wants to get on the ball and make things happen. He has a good engine on him and can get about the pitch.
"You fear nothing at John's age. He just wants to play football. He injects enthusiasm into our play as, for that matter, do Thomas Reilly and Kenny McLean.
"We have a very good blend of youth and experience and hopefully we can use that to our benefit between now and the end of the season."
The Saints will go into their William Hill Scottish Cup fourth round tie with Brechin in Paisley this weekend in confident mood.
But Teale watched Brechin take Rangers to extra-time in their Ramsdens Cup match at Glebe Park on the opening day of the campaign back in July before eventually going down 2-1 in overtime.
He said: "We have done well in the last two matches that we have played.
"But the expectation and pressure will all be on us this weekend and we have to handle that and perform.
"Brechin will be going out to enjoy the occasion and I know only too well that in a one-off game anything can happen.
"Brechin played a very strong Rangers team packed full of internationalists in their opening game of the season in a one-off cup game and took them to extra-time.
"That shows just what they are capable of on their day.
"But if we are all professional and apply ourselves properly at the weekend, then hopefully we can get a positive result and advance through to the next round."