Dane Scarlett scored in stoppage time to earn Oxford United a point against West Bromwich Albion in the Championship.
Karlan Grant’s first-half strike opened the scoring for the visiting Baggies, the forward stunning the home support into silence with his effort from outside the box.
The U's pushed for an equaliser and forced Albion deeper in the later stages of the second half before Scarlett eventually headed home from a well-worked long throw routine.
Oxford’s impressive home run continues as they remain unbeaten at the Kassam Stadium this season after winning promotion last term.
West Brom would have gone top with a win but now sit in fifth after conceding late on.
The first big chance of the match came in the sixth minute for Oxford’s Mark Harris.
He got in behind the Albion defence but a heavy touch took the ball away from him before Baggies keeper Alex Palmer managed to comfortably deflect the ball behind for a corner.
A portion of West Brom's early chances came from set pieces and they enjoyed a decent spell after 20 minutes when a few efforts went close, most notably Torbjorn Heggem’s header flying narrowly over the bar from a corner.
West Brom took the lead just before 30 minutes when Grant received the ball centrally in space just outside the box and set himself before sending a low shot into the bottom left-hand corner, in off the post.
Oxford nearly had the perfect response when Ciaron Brown met a corner with his head just after but his attempt flew over the bar.
It meant the home side went into the break trailing at the Kassam at half-time for the first time in this Championship campaign.
The second half started as a much more open game, both teams having joy getting forward and creating chances in front of goal.
All of the supporters in the ground were on their feet when Harris suddenly looked through on goal, using his body to get away from a Baggies defender and sprinting away.
However, referee Leigh Doughty pulled play back saying Harris used contact illegally, with Oxford boss Des Buckingham then picking up a booking for sharing his frustrations.
U's substitute Louie Sibley made an aggressive challenge on Alex Mowatt just before the 80-minute mark, wrapping his legs around the midfielder at pace and fairly high up on his leg but was only shown a yellow card as Albion players called for further punishment.
In the final moments of the game Oxford pushed the West Brom defence deeper into their own half and piled on the pressure.
Into five minutes of added time the U’s worked a decent long throw routine from Will Vaulks, whose launched ball was flicked onto the head of Scarlett, who glanced it into the net to register his first goal for the club.
Oxford 'didn't panic' - reaction
Oxford United boss Des Buckingham speaking to BBC Radio Oxford:
"We're happy with the second-half performance, we have come up against a really good team in West Brom who will I'm sure be challenging to get up and out of this league, so to get a result, we're very happy.
"In the second half there was a real clear way in what we did, there was an identity about us and we didn't panic despite the scoreline.
"It took us until the 93rd minute to finally score but we got there in the end and that's what matters."
West Bromwich Albion boss Carlos Corberan told BBC Radio WM:
"The feeling is that we have lost two points
"In the final moments of the game you have to protect the result, we didn't manage it well and we should have in those final minutes.
"We also had some possibilities to score in the second half but we weren't able to do so to get the result. If we score those then we would have more control of the game."