Arsenal: Theo Might Not Ever Regain Electric Pace After ACL Injury
It's an oft-used cliché that football is a game of two halves - but that's never been truer in the case of Theo Walcott on Saturday.
"His movement today has been the best I have seen anywhere for a long time" purred Roy Keane, a rare endorsement from the stern-faced man not exactly famed for his generosity.
It was 6pm, midway through the evening kick-off - and as the ex-Republic of Ireland midfielder waxed lyrical, Arsenal went for their half time oranges with a 1-0 lead over local rivals Tottenham.
In truth, it should have been more. For 45 minutes, an inspired Theo Walcott had run the Spurs backline ragged - his blistering pace and intelligent movement dragging the visitor's centre-half pairing of Michael Dawson and Val Chiriches from pillar to post.
It was an incredibly encouraging performance from a player who has promised so much, yet only sparingly delivered - and it would have had even the most jaded England fan mentally ticking off the days to Brazil.
"I've always said I'm a striker, and the manager is giving me the opportunity to play up front" said Walcott just before the turn of the new year.
"I'm not saying I'll play up front all the time, but it's just nice to have a different option".
Some would argue that he has, in fact, left Wenger with no option. An impressive 10 goals notched in 10 outings over the last month or two tells its own story - but two hat tricks in that time, alongside some frankly breathtaking performances, suggest that Walcott is finally ready to fulfill the world class potential he has shown for so many years.
His side had taken the lead a quarter of an hour before the break, as Santi Cazorla skilfully struck a perfectly weighted Serge Gnabry through ball to separate the sides - but it was the subtle input of Walcott which had the panel of experts drooling.
Arsenal legend Ian Wright highlighted the movement of the ex-Southampton youngster, whose clever burst effectively took two defenders out of the game, freeing up the space for Gnabry to find his Spanish teammate.
As Walcott took a well-earned break in the Emirates dressing room on Saturday evening, he would've been confident of adding to his recent goal haul - but, as we have seen time and time again, football can be a cruel game sometimes.
The second half saw Arsenal's dominance remain - in fact, they doubled their lead midway through the second 45 - but Walcott was not to see the final whistle.
Stretchered off with a knee complaint in the final throes of the derby, he was foolishly carried in front of the visiting Spurs fans, who pelted him with coins - to which he cheekily responded by gesturing 'two nil' with his fingers to the crowd.
At first glance, it was just a niggly injury - a four week lay-off. But today, Walcott was greeted with a much more grim diagnosis.
He faces a long road of recovery - six months, to be precise - and will miss the rest of the season, as well as the World Cup in Brazil this summer.
It is a depressing twist in the tale of a player who appeared to have found the form of his life in time to hit the biggest stage in the world.
A ruptured Anterior Cruciate Ligament is one of the most common footballing knee ailments - and has affected scores of players including Paul Gascoigne, Alan Shearer and Michael Owen.
Thankfully, treatment has come on leaps and bounds over the last few years, and what was once a career-ending injury, often now just requires an extended rest and some focused rehabilitation.
When Owen burst onto the scene with that wonder goal against Argentina at the 1998 World Cup, he cemented his place in English football history.
It could be argued that he never really regained the searing pace he possessed in abundance before tearing his ACL eight years later - and he eventually retired with a whimper last season.
As Walcott misses out on the World Cup which could have been the making of him, England fans will wonder what might have been.
Follow Jonno on Twitter, @JonnoT