It had seemed Miller-Rodney’s opener in the 65th minute, after a dreadful goalkeeping error, had given Jon De Souza’s side their first pre-season win.
They suffered from a collective lapse of concentration in added on time that allowed the home side two stabs at goal from a corner, the ball eventually landing past Gledhill’s goal.
De Souza was without the services of four players, who have been kept back for this Saturday’s first team game at Walsall, and was forced to replace them with first and second year scholars.
Goalkeeper Matt Gledhill returned for his second trial spell in goal after a similar period at Sheffield Wednesday last week and trialist - wing man Nick Vrančić - was given a starting place.
Antonio German was preferred up front with Charlie Adams making a welcome return on the bench after a spell out injured.
Brentford started brightly but with little penetration, the closest attempt being German’s header on 13 minutes, which lacked punch.
Midfielder Michael Onovwgiun should have given Brentford the lead in the 25th minute but he blasted over from ten yards out.
Stoke rarely troubled The Bees in the opening half, their only shot on target being parried by Gledhill on the half-hour.
Four minutes after the break German created a good opening for himself but his shot was deflected to safety.
It was the visitors that took the lead, in the 65th minute courtesy of Tyrell Miller-Rodney.
The Stoke goalkeeper was caught in possession in the six yard box by The Bees midfielder who had the simple task of tapping in from a yard out.
De Souza had made three substitutions by that time, which changed Brentford’s shape.
One of them was winger Montell Moore, who with striker Myles Hippolyte, had played a part in the under-18s match on an adjacent pitch; both of them being withdrawn from that game to take part in this one.
Moore tried a shot from long distance in the 80th minute but was well wide of the target.
With eight minutes remaining, a Stoke midfielder lunged into Charlie Adams, with the result that the referee walked him from the pitch and asked he be substituted by the Stoke City bench.
As Brentford were preparing for victory they switched off at a set piece and Stoke levelled things up.
Brentford line-up:- Gledhill; Bryan, Kamau, Pierre, Griffiths; Onovwigun, Miller-Rodney, Scott (sub Hippolyte 58 mins), Vrancic (sub Adams 63 mins); Clarke, German (sub Moore (M) 65 mins).
Note: Vrancic came back on for Bryan 75 mins and Bryan returned for Pierre 87 mins.