There is something floating in Ryan Harris' knee. The medical community thinks it is bone. It's probably magic. Or a little pebble of awesomeness. Nothing else explains his last over.

In the overs before, Harris could barely bend over when fielding at gully. His hands were at the top of his thigh, not down near his knee in the customary position. When he walked, you were watching someone with osteoarthritis move, or someone who had done a whole day of rodeo. And when he stood up at the end of each ball you could hear the creaking all around the ground. Even his hip flexor had given out, possibly from the flexing he was doing more and more just to get by. Crocked. Stuffed. Finished. Another over was surely beyond him. Another Test might have been as well.

His job was to stay out on the ground to celebrate the potential Australian win. The win that they couldn't get. Vernon Philander's hand and Dale Steyn's bloody-mindedness were drawing the Test. Here were two forces.

One, the South Africans, they just refuse to lose a Test series. They're better when the primal need for survival has been put on them by their own shoddiness. This time, they had extra motivation with their captain, hero and leader on his last mission. They couldn't have done more to draw this game if they decided to dig actual trenches at the Kelvin Grove end. Against them was a very movable force. The fluid in Harris' knee was moving the bone quite often.

Ryan Harris celebrates dismissing AB de Villiers Getty Images

Australia thought they'd get eight or ten overs out of him in the entire second innings. The wicket of AB deVilliers was in his fifteenth. You should never call this dismissal anything as dismal as a wicket. It was a triumph of man over superman. De Villiers is currently batting like the laws of physics don't apply to him. It is as if he has learnt to see into the future and decides on his shot as the bowler is coming in. Getting him out in this form, with his assistance is virtually impossible. Getting him out without his assistance from a busted down old man who should be on crutches should be impossible. The only thing impossible was the Harris outswinger.

Ryan Harris winces in the face of impossible.

Today he winced from leg slip, slip, gully, short cover, or anywhere else you put the guy who stopped being able to move. But he kept coming back, more broken than before.

Tasmania had tried to break Queensland during the last Sheffield Shield final. They had prepared a pitch made of actual deserts. They batted in a coma. And then when Queendlsand tried to move the game on, they picked up enough wickets to lead by almost 200 runs after the first innings. In the first innings, Queensland had bowled 173.4 overs. Harris had bowled forty of those and taken three wickets.

But in the second innings, he just kept going in his opening spell. It seemed endless. Harris, and everyone watching or playing, knew that the only chance of a Queensland victory was with him. Tasmania collapsed under his pressure to 5 for 16. Harris bowled what felt like all the overs, he smashed the ball into this lifeless pitch, he demanded that the ball move for him, and he put his entire career in jeopardy by bowling 54 overs for his adopted state in a losing cause.

It seems that Harris just cannot quit. So why would he listen to his surgeon, his doctor, his physio, or anyone, when they said he couldn't bowl again. He hadn't ever listened to his body. Fast bowlers don't start international careers over 30 in already broken down bodies and take over a hundred wickets. But Harris wouldn't listen to modern medicine, he wouldn't listen to science, he wouldn't even listen to cricket stats.

"It seems that Ryan Harris just cannot quit. So why would he listen to his surgeon, his doctor, his physio, or anyone, when they said he couldn't bowl again. He hadn't ever listened to his body. Fast bowlers don't start international careers over 30 in already broken down bodies and take over a hundred wickets"

His second last over of the day looked like his last, well his last of any note. He bowled a short quick one that scared Steyn. It was quicker than his over the previous night where he bowled an over of Shane Watson-paced slower balls.

But he didn't look right. Instead of bashing through the crease like a Joe Frazier combination, steaming coming from his nose, his chest daring anyone to hit him, his legs were all over the place, and his fearsome torso looked attached to the wrong set of legs. His knee wasn't working, his hip was flexing poorly, and he was trying to play through it all and conquer a pitch that gave nothing.

On the second last ball, he slipped as he delivered. It looked, for the shortest of moments, like the injury that could end him today, tomorrow and forever. But he just went back to his mark and somehow got through the over. He was now noticeably limping. His action and run up was falling apart. He had surely bowled his last over, or at least, his last of anything approaching pace.

Nathan Lyon was tried, but had little luck. Watson came back on to wobble them about a bit. And had he wobbled them slightly better, or at least had Steyn playing at them, Harris might not have come back when he did.

When he came on, you couldn't shake the feeling that Ryan Harris shouldn't be bowling. Ryan Harris shouldn't be walking. Ryan Harris shouldn't be bowling Australia to victory. Ryan Harris shouldn't be running around the outfield having just taken the two final wickets in three balls. Ryan Harris should be with a surgeon, showing him how when he twists his knee, the bone clicks out of the bad bit and he can walk properly again.

Where did he find the swing or strength?

In the years to come it will read 24.3 overs, 15 maidens, 32 runs and four wickets. But unless it was written in synovial fluid, tears, bone, tendon and blood, no one will ever understand how good Ryan Harris was today. Whatever is in that knee, I hope they remove it, and get Ryan Harris fit again. Then I hope they show the removed item in a museum and schoolkids are bussed in to see it for years to come.