You have a lot of work ahead of you.
I hate it when people use the term "pro" loosely, because it gives some misconception. That MK player was not pro. That Metaknight should really look on the boards and apply a bunch of the standard strategies, because that was really just a sad showing on his part. No gliding, no usage of any of his specials at the right times, and he approached you via aerial d-airs... That was horrible on his part. MK can easily approach Link on the ground, and it's a hell of a lot safer. He seemed to have almost no knowledge of MK...
You did okay, but you are missing a large core of what makes Link good. Read up on the ATs, and just get a feel for what it's like to projectile spam. That was FD, and I only saw a few bombs and almost nothing else. FD is like the easiest stage to projectile spam on. If you've played Link in either of the previous 2 games, you know that he's always been highly dependent upon it. Watch other Link players and see how they use their projectiles if you don't understand the basics.
Your air game, while lacking, wasn't nearly as glaring as your lack of projectile spam. You also seem to be amazingly spot dodge happy, you should really tone that down otherwise it'll become easily baitable. Learn to save your KO moves for KOs, and use other moves for racking up damage. There were a bunch of times a jab A would've been much more appropriate than f-smash, and I would recommend you grab more (although Link's throws suck for damage, it stops opponents in their tracks and allows you to regain control of matches, most of the time), but don't miss grabs.
I'm not trying to be harsh or anything, just giving you the truth. I am by no means a great Link player in Brawl, but I still have a decent amount of insight into how to play him (particularly his projectiles which are fundamentally unchanged) from my years of experience in SSB64 and Melee.
