EVERY season has its defining moments, and with one more game in which to determine whether or not they finish in the top two, Middlesbrough will be hoping last night’s refereeing controversy at Birmingham City does not come to be remembered as the incident that sealed their fate.

With the scores tied at 2-2 – hardly a catastrophic result, but not exactly an ideal one either – Daniel Ayala drilled home what looked to have been a perfectly-good winner. The Spaniard was half-a-yard onside when he received the ball from Jordan Rhodes, but inexplicably, the assistant on the touchline raised his flag.

It was a diabolical decision, but hopefully it will not be a decisive one. The £100m mistake? Boro’s job when they meet Brighton on Saturday is to ensure it does not prove that costly.

The Teessiders’ fate is still in their own hands after a pulsating night at St Andrew’s, and a last-day victory over Brighton will still guarantee promotion no matter what the Seagulls do when they meet Derby on Monday. Depending on what Burnley and Brighton do on the Bank Holiday, a draw could yet suffice.

Trailing to Stephen Gleeson’s first-half strike, Boro turned things around thanks to goals from Rhodes and Gaston Ramirez.

David Davis’ equaliser pegged them back, and even after Ayala’s goal was disallowed, Grant Leadbitter rattled the crossbar with a vicious long-range strike. The drama was unrelenting, but the tension will increase even further in seven days’ time. Trust Boro not to make things easy.

Last night’s opening 45 minutes was a tale of two goalkeeping errors, with the second considerably more catastrophic than the first. Dimi Konstantopoulos will feel he should have done better when Birmingham claimed the lead shortly after the half-hour mark; his opposite number, Adam Legzdins, will know he was completely to blame for Boro’s equaliser seven minutes later.

Konstantopoulos had displayed signs of edginess midway through the opening period when he could only parry Birmingham’s first shot on target, a long-range effort from Maikel Kieftenbeld, setting up a rebound opportunity for Clayton Donaldson.

To the Greek shot-stopper’s credit, he successfully clung on to Donaldson’s follow-up strike, but perhaps the incident persuaded the home side to try their luck from distance. When Birmingham next tested Konstantopoulos, they claimed the lead.

Ritchie de Laet could only direct a defensive header from Jonathan Grounds’ cross straight to Gleeson, and the Blues midfielder gleefully drilled home the rebound from 20 yards.

Konstantopoulos got a hand to the strike, but was unable to keep it out. The ball passed by two defenders on the way to goal, leaving the Boro goalkeeper partially unsighted, but that is an inadequate mitigation for his failure to keep it out.

That said, however, Konstantopoulos’ error was nothing compared to the howler committed by Legzdins shortly after.

Faced with a weak 25-yard free-kick from Ramirez, Legzdins had the ball in his grasp as he fell inside his six-yard box. Somehow, he allowed it to squirm away from him though, and Rhodes bundled home from close range. The Scotsman was tumbling to the floor as he finished, and his failure to celebrate suggested that even he couldn’t quite believe what had happened.

It was probably the only way Rhodes was going to score, as prior to claiming his fourth goal in the last four games, the striker had spurned two gilt-edged opportunities to fire his side into the lead.

The first was the easier of the two, with the ball breaking kindly for him inside the area after Leadbitter bundled his way through two challenges. Rhodes attempted to loft the ball over Legzdins, but was thwarted by the goalkeeper’s efforts.

Four minutes later, and a slick passing move involving Ramirez and Stewart Downing resulted in him being released beyond the Birmingham defence again. The opportunity was similar to the one he spurned against Ipswich last weekend, and the outcome was identical as Legzdins got down well to divert Rhodes’ shot behind for a corner.

Having arrived with a reputation for being clinical in one-on-one situations, Rhodes is still to fully convince on that score in a Middlesbrough shirt.

His persistence almost brought him a second goal six minutes after the interval, although it also prevented what might have been a successful strike from Albert Adomah in the same incident.

Rhodes’ predatory instincts were apparent as he lost his marker to latch on to Leadbitter’s hanging free-kick, and he was somewhat unfortunate to see his prodded volley roll against the left-hand post.

What followed next was something of a farce though, with Rhodes getting in the way of Adomah’s close-range follow-up effort before Ramirez blazed over with the goal at his mercy. With a degree of nervousness inevitable, minds appeared addled.

Things would have been even edgier had Ryan Shotton not headed David Cotterill’s free-kick just past the post at the start of the second half, but Boro were able to breathe easier as they regained the lead shortly before the hour mark.

To be fair to Rhodes, the goal owed much to his alertness, as he nodded Adomah’s cross back across goal when other players might have opted to take on the chance themselves. It was an astute move, as it afforded Ramirez the easiest of headers from inside the six-yard box.

Suddenly, the game was wide open, and Boro felt they should have had a penalty when Shotton appeared to bundle over Adomah in the area. Referee Simon Hooper waved play on, and if Boro felt hard done by on that occasion they were nursing even more serious wounds shortly after.

First came Birmingham’s equaliser though, with Davis cracking home a superb shot from the edge of the area after Ayala headed Paul Caddis’ cross into his path.

That rocked the Teessiders, but they should have been back ahead three minutes later. Downing delivered a free-kick from the right-hand side, and Ayala was comfortably onside as he received Rhodes’ pass. The Spaniard displayed impressive composure to sweep a shot into the right-hand corner, but was inexplicably flagged offside.

Former Boro midfielder Diego Fabbrini almost rubbed further salt in the wound when he headed over in the closing stages, and Konstantopoulos was forced to make an excellent late save from Cotterill to keep the scores level.

Leadbitter’s strike almost brought the crossbar down, never mind just rattling it, but the game ended with the Teessiders no closer to knowing their fate.