HU, 6-handed. Smallest flush facing reraise

Villain had been getting very frisky after i knocked everyone else out.

PokerStars Game #5342344943: Tournament #26939638, $12+$1 Hold'em No Limit - Level IV (50/100) - 2006/06/23 - 17:08:41 (ET)
Table '26939638 1' 6-max Seat #4 is the button
Seat 4: BigChip3 (2310 in chips)
Seat 6: baudib (6690 in chips)
BigChip3: posts small blind 50
baudib: posts big blind 100
*** HOLE CARDS ***
Dealt to baudib [2d 3d]
BigChip3: calls 50
baudib: checks
*** FLOP *** [Td 7s 9d]
baudib: checks
BigChip3: bets 200
baudib: calls 200
*** TURN *** [Td 7s 9d] [Js]
baudib: checks
BigChip3: checks
*** RIVER *** [Td 7s 9d Js] [4d]
baudib: bets 300
BigChip3: raises 300 to 600
baudib: ????

calls 300
*** SHOW DOWN ***
BigChip3: shows [8h 9c] (a straight, Seven to Jack)
baudib: shows [2d 3d] (a flush, Ten high)
baudib collected 1800 from pot
*** SUMMARY ***
Total pot 1800 | Rake 0
Board [Td 7s 9d Js 4d]
Seat 4: BigChip3 (button) (small blind) showed [8h 9c] and lost with a straight, Seven to Jack
Seat 6: baudib (big blind) showed [2d 3d] and won (1800) with a flush, Ten high

Heads up? With a 3-1 stack advantage?
On a 3-flush board? I could see just CALLING on a 4-diamond board, but really. If he has a bigger flush, nh gg.

yeah I suppose you're right. Everything about the line I took is consistent with a flush draw though.