We'll have a better idea after tonight. Gasol punched Garnett in the mouth in game 1 on the glass, and I think it was a (the?) deciding factor of game 1. In game 2, though, KG came to play before the fouls. I've gone through the stats of both of the first 2 games when KG and Gasol were each other's main assignments (i.e. when both are in the game, and Odom is out). The totals from game 2 look like this:
17.15 minutes
Gasol: 4 points (2-for-2 FG), 6 rebounds (2 offensive), 2 assists
Garnett: 4 points (2-for-4 FG), 3 rebounds (0 offensive), 4 assists
Gasol still won the battle of the boards, but it was at least competitive (vs the 8 - 0 rebound shellacking he laid on KG in game 1, including 5 offensive boards). And KG arguably had the larger offensive impact in game 2 when they were guarding each other, with his passing helping to change the game. Gasol scored 21 points on 8 shots in the 25 minutes he was out there without KG as his main defensive assignment. He definitely had a huge game, but unlike game 1 Gasol's big night in game 2 can't be tied to him producing on Garnett.
Also, let's look at how game 2 broke down by quarter:
1st quarter: Garnett had 2 points, 2 assists and a rebound in the first 3:26 before he got called for that 2nd foul 50 feet away from the ball. Gasol had only a defensive rebound in that period. All signs were that Garnett was about to ball, then he had to go to the bench.
2nd quarter: KG seems tentative trying to not get the 3rd foul, but of course he does in only 2:37. Neither he nor Gasol even attempted a shot before he had to go back to the bench.
3rd quarter: Having played a total of 6 minutes in the first half, Garnett is now completely out of the offensive flow and playing careful on defense to avoid another foul. He makes it 5:41 before he gets the foul this time, but he misses both shots that he attempts (one of them badly). Meanwhile, this is Gasol's "aggressive" period against KG, scoring all 4 of his points on 2-for-2 shooting, dishing both his assists and grabbing an offensive board.
4th quarter: By this time KG seemed to say 'forget it' and just went out and played, since he had 2 fouls to burn. And as many have pointed out, in this quarter he made several big plays on both sides of the ball. Also of note, during the 5:25 when they guarded each other Gasol was held without a point or assist despite it being the most important period of the game.
Bottom line: it sure looks to me from the start and finish, when Garnett was able to just play without worrying about fouls, that he was playing impact ball and getting the better of his matchup with Gasol. But that is a vanishingly small period of time with which to make a conclusion, and given Gasol's big game 1 and big-time scoring when KG wasn't on him (as well as his 6 huge blocks) he's more than earned the benefit of the doubt in this match-up right now.
That's why I need to see what happens in the next couple of games before I can really gauge this. Round 1 went to Gasol (primarily on the glass) with a knock down, while Round 2 could have been a draw in their head-to-head but KG's foul difficulty gave Gasol an easy 10-9 round on the scorecards. What I need to see now is if Garnett has the counterpunch in him that I expect, or whether Gasol is ready to resume control again. Looking forward to tonight to start answering that question.