The Knights had a lot of possession in the opening hour while Watsonians had three men in the sin bin at various stages.
As a result, the home side were 13-0 up at that stage, but should have had more points. And they were made to pay when centres Joe Reynolds and Lewis Berg scored tries converted by captain Lee Millar for the Edinburgh side as they secured a 14-13 triumph.
“Our defence was outstanding, we only conceded one try and that is when we were down to 14 men, I think that defence won us the game,” Pringle said.
“When we were 13-0 down with three yellow cards, I wasn’t sure if we could go on and do it, but the boys really stuck in.
“We were lucky, we gave away a lot of penalties and you don’t normally give away that many and win. In the second half we started to get a foothold in the game and, although the Knights scored a try, the boys didn’t panic.
“We then managed to take two chances when they came along.”
His opposite number Rob Chrystie was left to rue one that got away.
The Greenyards coach said: “Credit to Watsonians, I thought they were pretty physical with some big old units and they took their chances.
“They rode the storm at the right time and were a bit more accurate when they got into our 22.
“It is going to be scary from our perspective looking back at the video and seeing how often we got into their 22 and didn’t get over the line, so that’s something for us to work on.”
The game started at a quick pace, but as the 15th minute came and went it was still scoreless.
Melrose then earned a penalty in front of the posts and went ahead in the 16th minute thanks to three points from stand-off Struan Hutchison.
In the 26th minute Hutchison kicked a second penalty and Watsonians back-row Michael Badenhorst was yellow carded.
He returned, but then centre Lewis Berg was sin-binned for a yellow card. Half-time arrived and it was still 6-0 to the home side.
Fourteen minutes into the second half, Watsonians second-row Jamie Hodgson became the third player yellow carded and four minutes later the Knights scored the first try of the day through winger Michael Mvelase-Julyan, Hutchison converting.
Then came the Watsonians comeback. The forwards started to carry with more purpose and in the 63rd minute a neat kick through by Millar was collected by centre Reynolds who scored. Millar converted for 13-7.
Six minutes late try number two came after some strong phases when Berg burst through to score. Millar again converted to make it 14-13 and some strong defence in the last few minutes saw the visiting team home.