Sphinx boss Paul Charnley named a mixture of experienced youth for this game on a sunny evening.
It was the Midland Combination Premier Division side who took the lead in the third minute when Royce Turville raced clear to chip the ball over Chris Daffern from twenty two yards.
In the 15th minute, Sphinx almost equalised when Kyle Rhodes got in a header which St John keeper Tom Gutteridge superbly pushed one handed over the bar for a corner.
But it was Heather who were the next team to get the ball into the net. An inadequate wall gave Kevin Allsopp the space to curl home a 24th minute free kick.
Nine minutes later and two became three thanks to Justin Kisblewicz finding space inside the penalty area to rifle home.
At half time, Sphinx were 3-1 down with Luke Hopkins pulling one back for Sphinx in the 43rd minute. The striker hit a 25 yard shot on the turn which took a deflection and flew high into the net.
Both sides made changes at the break and after Sphinx Man Of The Match Gary Mead had been replaced, the arrears were reduced again when a Jez Carpenter shot hit the bar and Fidel Hinte rammed home the loose ball.
Another product of Sphinx's youth team Liam Jordan had a fine game, playing at left back. The youngster made some superb tackles and was always looking to push his team mates forward in hope of an equaliser.
Six minutes from time, Sphinx did tie the match when Hunte fed Chris Harris on the right side, some twenty yards out and the striker cooly finished with a low drive into the bottom corner to delight the Sphinx support which included Coventry Bees rider Rory Schlein.
Sphinx now travel to Woodford United on Saturday.
Sphinx
Daffern,Mead,Holmes,Rhodes,Wilks,Kay,Fisher,Halton,Hopkins,Harris,Irwin
Subs Used GK Huddlestone,Carpenter,McAteer,Hinte,Jordan,Kimberlin