The Royals started brightly, earning two corners in the first two minutes - both cleared by the Brentford defence.
Ejaria and Olise did well to begin a counter attack eight minutes in which saw Semedo centre the ball lookiong for Joao. Again a Bees defender intercepted but Yiadom recycled it and won a corner when his deflected cross spun behind.
Both teams were full of energy and intent and the intensity was there for all to see, both sides biting into tackles and harrying their opposite number as soon as they were in possession of the ball.
Yiadom cleared two successive corners from the Brentford left and Reading countered from the latter, Joao so nearly preying on a pass back to Raya which looked like it might not reach the Bees keeper for a moment.
The visitors got their first shot away from the right foot of Toney but the ball deflected harmlessly wide and behind for a goal kick.
And Reading deservedly took the lead in the 25th minute. Morrison found Ejaria with a superb crossfield ball and he laid the ball into the feet of Laurent just inside the Brentford box. As he looked to pull the trigger, Henrik Dalsgaard seemed to clip the midfielder's heels and Laurent took a tumble.
The referee immediately pointed to the penalty spot and Lucas Joao stepped up to tuck away his spotkick low past the fingertips of Raya and in off the base of the left upright.
The visitors, unbeaten in their lasy 20 games, looked to respond quickly and upped their intensity to another notch. But the Royals were equal to it, Yiadom sliding in to deny Fosu a shot or a cross towards the loitering Toney.
And Reading nearly carved out a second when Richards burst onto a charged down Laurent shot, scurried down the left side of the box and flashed a low cross across the six yard box and just in front of Joao in the middle.
But the Bees were level with nine minutes of the first half remaining. Josh Dasilva barged his way into the box down the right from a quickly taken free kick and he lashed a powerful effort high inside the left post for 1-1.
Reading nearly refound the lead immediately, an early cross from the right from Yiadom was won in the air by Joao and Raya had to tip the ball over his crossbar.
Joao then got in behind the Brentford back line to stride onto a lovely ball from Richards, but as he dragged the ball into a shooting position inside the Brentford box, Ethan Pinnock slid in to get a toe to the ball and touch it onto the leg of Joao and behind for a goal kick.
And as the interval approached, again the Royals came close. Laurent jinked his way into a shooting position and swung a right boot at the ball, but Raya was in the right place to parry it and it was shuffled behind for a corner before Yiadom could pounce on the loose ball.
Half-time: Reading 1-1 Brentford
There was no let up in the second half. Rafael came out of his goalmouth to clear the danger from a direct ball from deep that Toney threatened to run onto.
The Royals then broke in turn, Olise getting the ball to feet down the right side of the Bees' box, cutting back onto his left foot and see his shot ricochet off a Brentford body and spin just wide of the bottom right corner.
On the hour, a free kick just inside the visitors' half was floated onto the head of McIntyre who nodded the ball down for Yiadom in a yard of space. But his touch denied him the chance to shoot and the ball rolled behind for a goal kick.
Thomas Frank brought on Sergi Canos whose first input saw him run onto a Toney flick on and loft the ball over the top of the Reading defence looking for Dasilva - but Morrison was across well to scramble the ball clear before the midfielder could trouble Rafael.
Brentford were starting to build some pressure and Richards did brilliantly to track the run of Canos and see the ball out for a goal kick.
And Richards was again on the ball to deny Toney a shot at goal after a Dasilva pass into the Reading box had threatened to fall for the free-scoring striker.
Dasilva burst past Ejaria to reach the byline down the right and his low cross into the six yard box was superbly cleared by Morrison.
Going into the final ten minutes, somehow both teams had sustained the intensity they began the match.
But Brentford found the winner. A deep cross from the left was chested down by Toney and Dasilva hammered the ball high into the net past the helpless Rafael with a close range volley that sent the away bench wild.
And the three points were in the bag when they found a third late on. Canos drilled a low shot at goal which Rafael got down well to parry, but Toney was first to the loose ball and slotted the ball home from close range for 3-1.
An Olise free kick deflected off the Brentford wall and wide for a corner and the assistant referee saw an infringement in the area to halt any Reading opportunity from that set piece.
But the points were Brentford's at the end of a pulsating encounter.
Full-time: Reading 1-3 Brentford
Reading: Rafael, Richards, Yiadom, Morrison (c), McIntyre, Rinomhota, Laurent, Olise, Semedo (Aluko 77), Ejaria (Holmes 90), Joao.
Unused subs: Southwood, Esteves, Gibson, Tetek, Onen, Camara, Baldock.
Yellow: Richards
Goals: Joao 25 pen
Brentford: Raya, Henry, Pinnock, Jensen (Forss 90), Dasilva (Zamburek 90), Dalsgaard (c), Mbeumo (Canos 64), Janelt, Sorensen, Fosu (Ghoddos 80), Toney.
Unused subs: Daniels, Reid, Roerslev, Zamburek, Stevens, Gilbert, Forss.
Goals: Dasilva 36, 85, Toney 88.