Following a dull first half, Son fired Spurs ahead with a superb, trademark strike from distance before doubling their lead with a cool finish inside the box.
Danjuma, a second-half substitute, marked his debut with a first-time finish to see off the Championship side.
Dan Kilpatrick was at Deepdale to rate the Spurs players…
Fraser Forster 6
Untested, aside from routine saves but commanded his area well.
Japhet Tanganga 7
Pushed forward and set up Son’s first goal, albeit with a simple pass.
Davinson Sanchez 6
A few jittery moments when running towards his own goal but did enough for the clean sheet.
Clement Lenglet 5
His distribution, usually a strength, was erratic.
Matt Doherty 5
Offered little from wing-back on a quiet evening.
Rodrigo Bentancur 7
Sloppy at times but looked a class apart on the ball.
Yves Bissouma 6
Kept the ball moving nicely but is still lacking the dynamism that characterised his displays at Brighton.
Ryan Sessegnon 4
Final ball was consistently awry in a hesitant display. Improved slightly in the second half and Perisic headed his cross goalwards.
Dejan Kulusevski 7
Had a couple of efforts blocked in the first half and looked a threat when he got on the ball, setting up Danjuma’s goal.
Heung-min Son 9
Scored two brilliant goals in his liveliest display in months. Twice tested Preston goalkeeper Freddie Woodman in the first half, too.
Ivan Perisic 6
Largely peripheral in an auxiliary centre-forward role for the first 70 minutes but did test Woodman with a header and assisted Son’s second.
Oliver Skipp (Bentancur 72′) 6
Composed on the ball.
Arnaut Danjuma (Sessegnon 72′) 7
Went up front on his debut and grabbed a well-taken goal, which should fill him with confidence.
Emerson Royal (Doherty 72′) 6
Solid at wing-back.
Bryan Gil (Son 86′) N/A
Not enough time to impress.
Subs not used: Austin, Hojbjerg, Kane, Dier, Davies.