The clash went down to the final kick of the afternoon when visitors Shrewsbury, trailing 20-19, saw a twice taken conversion attempt strike the post and drop to safety.
Two Ben Lewis penalties to one from Shrewsbury had given the Hornets a narrow advantage before Telford’s Dillon Read made an interception and ran three quarters of the pitch unopposed to score under the posts. Lewis added to conversion to give Hornets a 13-3 lead.
Shrewsbury rallied and cut the deficit before half-time with an unconverted try, but then saw one of their forwards sent off.
Being down to 14 men seemed to spur Shrewsbury on and they cut the gap to two points with another penalty.
But as they pressed again, a mistake at a line out saw the ball run loose which allowed Read to attack the blind side. He exchanged passes with Matthew Bird before touching down under the posts. Lewis added the conversion to make it 20-11.
A thrilling finish saw Shrews score a penalty before forcing a late try to leave them trailing by just a point with a conversion attempt to come.
The first attempt missed the posts, but had to be retaken as Hornets were out of the blocks too early. But the second effort hit the upright and bounced back to safety.
Hornets’ reward is a quarter-final tie at home to Kidderminster Carolinians.