A 10-10 draw proved to be a fair result between two evenly matched teams in Friends' School and Coleraine Grammar School, and now the duo will have to clash again to determine who reaches the fourth round (Wednesday, 2.30pm).
Friends' attacked early on but the stout Coleraine defence held firm before going up the opposite side of the pitch to register two excellent tries.
The first came as the result of a turnover with Daniel McCreedie cutting through and making ground. Quick ball was won and the forwards rumbled ahead for James Millsop to crash over. Nine minutes later, they added another try although the conversion was once again missed.
It again came following an outstanding effort from the forwards with man of the match Peter Wisener to the fore. Hugo Mawhinney gathered a loose ball and took off to score.
Friends' eventually got on the scoresheet just before the interval when Ben McCaughey kicked a penalty.
After the restart, Coleraine had the majority of the possession but just could not breech the home line.
With 12 minutes remaining, Friends' struck when their talented centre George Pringle burst down the left and linked with winger Bradley Mulholland, who touched down for McCaughey to goal and earn a replay.
Friends' other centre and Irish Sevens player Curtis Dundas made a few breaks in the game, while up front Conor Hall was dominant in the line-out and prop Ross Stewart put in many crunching tackles.
Friends' coach Stephen Robinson said: "It is never good to travel and I felt we had a couple of opportunities to clinch victory but you have to take what you get. Either side could have won but we had to defend for a lot of the second half. Thankfully we came through without too many injuries."
Coleraine coach Richard Boyd added: "It was an entertaining game between two teams testing each other. It was free flowing and fairly played with both teams showing a lot of discipline as only seven penalties were awarded during the game."