Speed is of the essence. I even timed the first fight on a stop watch, and read it as fast as I felt the action was moving: 34 seconds!
In thirty-four seconds Jason Bourne could kill sixty-eight well trained, heavily armed bodyguards.
Think about it.
If you feel like your fight IRL would last thirty-four seconds, then you're not watching a fight. You're watching a sporting event with lots of rules designed to prolong the battle.
You pit two extremely well trained fighters against each other, that fight is going to be over very, very quick. It doesn't matter if they're fighting with knives or fencing swords or guns or their bare hands. With very little exception, somebody's going to make a mistake, or the other guy's just going to be faster, more often than not, somebody's going to get lucky. And boom, the fight is over.
If you're writing an epic Jedi fight where the fight goes on for twelve minutes and nothing is really happening, then we're not talking about a fight. We're talking about a dance. You see what I'm saying?
In all of my one-on-one fights, I make it a point to start and end the battle within a single short-to-moderately-sized paragraph. That doesn't necessarily mean that somebody's dead at the end of the paragraph, but in a real fight, we're talking quite a lot of buildup followed by three seconds of action tops, and then maybe some puttering around. Usually if you knock a guy down in a fight it's all over, there's generally just no coming back from that.
Realism and momentum is the key. If you can end the fight in three sentences or less then you don't need to worry about being overly wordy fight that's going to confuse or annoy your readers.
Some people like big epic battles where people can just fight for-frickin'-ever, but those people probably have no idea how to fight. If you want to build a fight that is not only exciting but is going to please your more scrutinizing readers, do it that way.
Another technique I use is to use run-on sentences with my fight scenes. Run-on sentences, while typically taboo, can be very well utilized during a fight scene. It helps sustain the upward momentum throughout an entire fight. So if you wind up having three sentences of a fight, from beginning to end, try taking out all the periods. Hell, try taking out all the commas. See what that reads like.
I swung my fist at his face but he was too fast for me. Before I knew it he shifted to the left and dodged my blow, stepping into me so that his shoulder was hard into my armpit. Braced against me, he flung my feet off of the floor and sent me crashing onto my back, knocking the wind out of me. That would have been it for me, but I grabbed my knife up off of the floor and backhanded it into his Achilles tendon. He screamed and fell off balance. I rolled into him and sent him tumbling onto his back. He was too stunned and in pain to see me finishing my roll by hammering the knife square into his chest. In one sharp pound it was buried to the hilt, and all I heard after that while I caught my breath were the ragged gurgles of the better fighter struggling to come to terms with the fact that he's dying because I got lucky.
Not bad, and fairly succinct despite going on for eight sentences. But how much more potent could that fight be if we not only shortened the overall length, but also took out several of the commas and periods in order to keep the momentum going?
Before I even started to swing he was stepping into me so that his shoulder was braced under my armpit, an instant later I was crashing into the floor and gasping for air. He stepped with me, the fight already over in both our minds, until my hand found the knife I'd dropped earlier and I quickly backhanded it into his Achilles tendon, sending him stumbling and screaming. Rolling into his legs he fell onto his back, still too stunned and in pain to even register what was going on with me, I brought his attention back where it should have been by hammering the knife square in his chest, burying it to its hilt, and the screams were replaced instead by the ragged gurgles of the better fighter dying because I got lucky.
This is just unpolished generic crap I came up with over the past five minutes, but you can see how I reduced eight sentences to three, and the momentum was significantly enhanced without really losing any relevant information. The same fight occurred, but one could be read in much less time than the other due to the less frequent breaks, which helped keep the pace of the fight. Also, speaking of keeping the pace of the fight, you'll notice that there are only periods at the end of each exchange. The first exchange being the winner throwing a punch and totally getting taken down. The second being him luckily landing near a knife and being able to grab it up, turning the tables by slashing the loser's vital area. The third is him striking the killing blow, and him registering that the fight was truly over.
The other thing is, if you take notice of where I put commas, it was only after each significant move. His punch wasn't significant as it didn't land, but the loser catching him in the shoulder was. The second comma with him stepping isn't relevant, though it provided a break for a quick info dump, that by any realistic standards the fight should be over, with the man on his back the loser, which both lets you know that the man on his back isn't the better fighter, while also letting you know that it's not over yet, and that something else is coming. Then him backhanding the knife into the guy's Achilles tendon, etc. etc.
Anyway, brief is best. You can choose to leave things up to your reader's imagination if you want, but with the exception of horror and unknown circumstances that the reader isn't actually observing, it's pretty lazy writing to have your reader to your work for you. Let your reader use his imagination by visualizing what you're writing, not by completing the story you're not telling him because you're not good at writing fight scenes.