LeBron's Finals stats:
Iguodala on Bench: 44% FG, 82% FT, 47% eFG, +30 +/-, 107.4 offrtg, 88.6 defrtg, +18.8 netrtg
Iguodala on Court: 38% FG, 66% FT, 41% eFG, -55 +/-, 94.1 offrtg, 109.7 defrtg, -15.5 netrtg
Iggy's stats:
Iguodala Finals: 37.1 min, 16.3 ppg, 5.8 rpg, 4.0 apg, 53% FG, 40% 3P, +10.3 +/-
If it wasn't his matchup with James then I don't know what it was either. He won them the series.
You could argue that his acceptance of a bench role during the regular season and then excelling against James as a starter in the Finals was part of it as well and I'd agree. Beyond that I don't know what's left.