The 18-year-old was thrown into the firing line after number one Artur Krysiak sustained an injury and he played his part in a thrilling 3-2 win for the Grecians in Saturday's League Two clash at Roots Hall.
"He played really well and made some good catches," Tisdale told the Western Morning News. "It was hard to kick it as his standing foot was slipping. It was a real baptism of wind, not fire! It was a really tough game, so well done him.
"We had to wait until 1.30pm when he went out to warm-up and I deliberately left the number one line empty on the teamsheet. I had a feeling we might be speaking to Christy at the last minute and we were.
"Sometimes when you are making your debut at 18, it is the best way to do it. It is a shame his parents couldn't be here - I am assuming they weren't here - but sometimes it is the best way.
"We got a win and Christy has come out of his first Football League match, so well done him."