The Paisley side face the Hoops in the quarter-finals of the Scottish Cup just three days after Neil Lennon's men lost to Motherwell at Fir Park.
That 2-1 Scottish Premier League defeat also comes after Saints stunned Celtic in the semi-finals of the Scottish Communities League Cup final last month.
In that match, St Mirren secured a surprise 3-2 win over the Glasgow giants to bring to an end a run of eight successive defeats that had seen Celtic amassing a combined score of 22-0.
Now Teale, who returns to boss Danny Lennon's squad after missing three games with an abductor tear, believes Celtic will be all fired up after those disappointments.
However, following their own 2-0 SPL success against Hearts in midweek, the 34-year-old claims Saints fancy their chances.
The former Scotland international said: "The worst thing that could have happened for us was Celtic's defeat to Motherwell.
"They will be even more up for it now, especially after that semi-final defeat too.
"But we can only concentrate on ourselves. We will take confidence from that result at Hampden. Celtic are a fantastic side and nine times out of 10, they will be expected to beat us, as their record shows.
"But we can take confidence from that last game and from the Hearts win as well.
"We will go in believing we can win again."