How can this happen in a heads up match?

[cryptcougar]

PokerStars Game #24274068004: Tournament #136423834, $11.00+$0.50 Hold'em No Limit - Match Round I, Level I (10/20) - 2009/01/25 18:19:03 ET
Table '136423834 1' 2-max Seat #2 is the button
Seat 1: cryptcougar (1200 in chips)
Seat 2: Pyykkikori (1800 in chips)
Pyykkikori: posts small blind 10
cryptcougar: posts big blind 20
*** HOLE CARDS ***
Dealt to cryptcougar [Ah Ts]
Pyykkikori: raises 40 to 60
cryptcougar: calls 40
*** FLOP *** [4h 6h 2h]
cryptcougar: checks
Pyykkikori: bets 80
cryptcougar: raises 120 to 200
Pyykkikori: calls 120
*** TURN *** [4h 6h 2h] [Kh]
cryptcougar: checks
Pyykkikori: checks
*** RIVER *** [4h 6h 2h Kh] [Js]
cryptcougar: checks
Pyykkikori: bets 520
cryptcougar: raises 420 to 940 and is all-in
Pyykkikori: calls 420
*** SHOW DOWN ***
cryptcougar: shows [Ah Ts] (a flush, Ace high)
Pyykkikori: shows [3h 5h] (a straight flush, Deuce to Six)
Pyykkikori collected 2400 from pot
*** SUMMARY ***
Total pot 2400 | Rake 0
Board [4h 6h 2h Kh Js]
Seat 1: cryptcougar (big blind) showed [Ah Ts] and lost with a flush, Ace high
Seat 2: Pyykkikori (button) (small blind) showed [3h 5h] and won (2400) with a straight flush, Deuce to Six