Overpair turns into flush

[johnny_fish]

No reads. Any suggestions how to play this optimally?

** Game ID 541741897 starting - 2005-10-15 20:26:00
** Detached Daddy [Hold 'em] (0.10|0.20 No Limit - Cash Game) Real Money

- snakeaye sitting in seat 1 with $9.65
- pillafa sitting in seat 2 with $20.42
- acesful sitting in seat 3 with $2.80
- Stoneburg sitting in seat 4 with $20.15 [Dealer]
- johnny291281 sitting in seat 5 with $29.35
- Emma11 sitting in seat 6 with $5.10
- Voozburg sitting in seat 7 with $17.40
- MagnusK sitting in seat 8 with $29.80
- yanino sitting in seat 9 with $9.10
- Gahlster sitting in seat 10 with $20.00 [Sitting out]

johnny291281 posted the small blind - $0.10
Emma11 posted the big blind - $0.20
** Dealing card to johnny291281: King of Clubs, King of Diamonds
Voozburg folded
MagnusK folded
yanino folded
snakeaye folded
pillafa called - $0.20
acesful folded
Stoneburg called - $0.20
johnny291281 raised - $1.10
Emma11 folded
pillafa folded
Stoneburg called - $1.10

** Dealing the flop: 2 of Diamonds, 10 of Diamonds, 10 of Hearts
johnny291281 bet - $2.00
Stoneburg called - $2.00

** Dealing the turn: 9 of Diamonds
johnny291281 bet - $3.00
Stoneburg called - $3.00

** Dealing the river: Jack of Diamonds
johnny291281 checked
Stoneburg bet - $6.00
johnny291281 called - $6.00

[allLiving]

This is tough because he might be betting the river because that's the only way he can win. I'd personally call this river. Also you need to turn up the aggression PF, post flop and on the turn.

[johnny_fish]

PF-raise was 5BB (standard). Flop was potsized, turn was half the pot. I don't see why it should be more aggressive.. Please explain.

Anyway, the outcome. He showed 22 for the FH. I thought I had pot odds to call the river, he could be bluffing or he could have T9/JT/QT/ with 1 diamond. Stupid?