It wasn't all past kendo experience though, and he gained a considerable skill thanks to the game. Kirito has become quite good at dodging attacks by the narrowest margin (a key to any martial skill). Due to his lack of muscle, his weakness is in attacks, parrying, and clashing weapons.
At least he's not so much of an ass anymore. He was actually willing to start up sparring with Sugu, something he selfishly forced her to do so that he wouldn't have to (per the Silica episode).
Sachi? That's a tiny Yui sprite in his pocket during the OP.
The only question is who the blond in the elf game is played by, but it's probably quite obvious given Sugu's line after they finished sparring (around 8:50). He was willing to restart kendo, and Sugu also started an activity that she's keeping a secret for now. Oh...whatever could it be in an anime about online games?
edit:
Wrong.
As much I have criticized it previously in this thread, they were quite clear that regular attacks and dodges are all the player's own movements, and skills are activated by rudimentary mimic movements of what you want to accomplish (basically, an appropriate waggle on a Wii game). It was only a skill when the weapons glowed. That's why Kirito's line made sense. He's good at the dodging, but the actual skill attacks are his new weakpoint. He got too used to being lazy and doing them only partially. The foundation is there, but he can't follow through because of the auto-complete once a skill is activated.
He could dodge and swipe at Sugu, but once he tried something fancy, he sucked.