This hand here, not been playing against oppo for long, think he's quite a decent HU player. Its a HU Cash table 20nl.
I think the best move is possibly to check the turn? He's called a big bet on the flop, felt he'd call the turn bet.
I have

, villain has £17.92
I have £21.20 s/b, I minraise button 2 40p, Villian 3 bets to 0.80, I 4 bet to £2.40, villain calls, pot is £5.60
Flop,

Villian checks, I bet £4.80 he calls, pot is £15.20 (villain has £10.52 behind)
Turn

villain checks, I set him all in.
LARSON7 Small blind £0.10 £0.10 £21.20
x Big blind £0.20 £0.30 £17.92
Your hole cards A K
LARSON7 Raise £0.30 £0.60 £20.90
x Raise £0.80 £1.40 £17.12
LARSON7 Raise £2.40 £3.80 £18.50
x Call £1.80 £5.60 £15.32
Flop
2 K 9
x Check
LARSON7 Bet £4.80 £10.40 £13.70
xCall £4.80 £15.20 £10.52
Turn
8
x Check
LARSON7 All-in £13.70 £28.90 £0.00
xFold
LARSON7 Muck
LARSON7 Win £14.44 £14.44
LARSON7 Return £13.70