Was 3-betting the river really wrong here?

[Wada]

Party Poker 0.50/1 Hold'em (10 handed) converter (http://www.selachian.com/tools/bisonconverter/hhconverter.cgi)

Preflop: Wada is UTG+2 with A/images/graemlins/club.gif, Q/images/graemlins/diamond.gif.
UTG folds, UTG+1 calls, <font color="CC3333">Wada raises</font>, MP1 folds, MP2 folds, MP3 folds, CO calls, Button folds, SB folds, BB folds, UTG+1 calls.

Flop: (7.50 SB) A/images/graemlins/spade.gif, 7/images/graemlins/spade.gif, A/images/graemlins/diamond.gif <font color="blue">(3 players)</font>
UTG+1 checks, <font color="CC3333">Wada bets</font>, CO calls, UTG+1 calls.

Turn: (5.25 BB) 2/images/graemlins/club.gif <font color="blue">(3 players)</font>
UTG+1 checks, <font color="CC3333">Wada bets</font>, CO calls, UTG+1 calls.

River: (8.25 BB) 8/images/graemlins/diamond.gif <font color="blue">(3 players)</font>
UTG+1 checks, <font color="CC3333">Wada bets</font>, <font color="CC3333">CO raises</font>, UTG+1 folds, <font color="CC3333">Wada 3-bets</font>, CO calls.

Final Pot: 14.25 BB

Results in white below: <font color="white">
Wada shows Ac Qd (three of a kind, aces).
CO shows 7c 7h (full house, sevens full of aces).
Outcome: CO wins 14.25 BB. </font>

[HajiShirazu]

This is close but a lot of players will play the other ace with an unpaired kicker the same way. In fact I usually wait until the river to raise if I have AAAx against the preflop raiser (if the pot is not that big) because I get called more often there by his KK/QQ but don't have to worry as much about the 3-bet from the bigger ace.

[MarkD]

I don't think the river 3-bet is that close really. I think it's clearly the best play.