In the seventh minute, Spurs took the lead. Son turned back onto his right boot having sprung the offside trap and drilled low at goal. Morrison blocked it successfully but the ball shot off the centre-half's outstretched leg and ricocheted off the unfortunate Omar Richards who deflected it into his own net under pressure from Lucas Moura.
Moura got away down the right himself soon after and squared the ball low for Son, who swept the ball goalwards. Rafael got enough on it to take the sting out of the shot and McIntyre followed it in to clear the ball off the line just before it rolled into the back of the net.
Lucas Joao came close moments later at the other end, connecting well with a cross from the left but placing his sidefooted shot just wide of the right post.
Dele Alli added a second though as Spurs took advantage of the pressure they were creating. Alli collected a one two from Lucas Moura and as Rafael came off his line to narrow the target, the England midfielder cleverly lifted the ball over the Brazilian keeper to watch it drop into the back of the Royals net for 2-0.
Joao was looking the most likely to find a reply and he combined well with Swift on the edge of the Spurs box, collecting the ball back from his teammate before placing a right-footed effort towards the bottom right corner but wide of Lloris' goal.
Josh Laurent tested Lloris' handling from distance, a skidding shot collected by the Tottenham stopper low to his left. Then a driving run from the Royals' new signing saw him burst into the box down the left side - and his shot took a deflection to send it just wide of the near post and behind for a corner.
But Spurs were clinical once again to add a third before half-time, Steven Bergwijn escaping down the left and feeding Son in the middle, who this time gave Rafael no chance with a fine finish inside the right post.
Yiadom brilliantly skipped away from Gedson Fernandes down the right and crossed into the middle to find Joao rising high. But the striker couldn't direct his header on target in the last chance of the first half.
Half-time: Spurs 3-0 Reading
Jose Mourinho made a flurry of changes to his side at the break, while Mark Bowen swapped Michael Morrison for Tom Holmes at the back.
Swift had an early chance to test the new Spurs keeper, Joe Hart, but his set piece was far too high to cause any trouble for the substitute.
Erik Lamela did somewhat better with his opportunity from a dead ball situation. Cannily arcing the ball beyond the Reading wall and wide of the outstretched arms of Rafael to make it 4-0 with an elegent set piece finish.
George Puscas came off the bench to stab an effort into the side netting near the hour mark - following good work from McIntyre and Rinomhota to release the Romanian inside the Spurs box.
With ten minutes to go, the Royals got themseles on the scoresheet. McIntyre did brilliantly to win a a free-kick on the left side and Swift swung the set piece into the box. Baldock's glancing header was superbly clawed away by Gazzaniga, then Holmes could only bundle the loose ball against the post. Puscas hooked the ball goalwards from close range but it was blocked on the line by the hand of Carter-Vickers. The referee pointed to the spot and Puscas gave Gazzaniga no chance with a fine spotkick to make it 4-1.
Full-time: Spurs 4-1 Reading
Tottenham Hotspur: Lloris (Hart HT (Gazzaniga 75)), Gedson (Aurier HT), Alderweireld, Dier (Carter-Vickers HT), Davies (Sessegnon HT), White (Sissoko HT (Devine 86)), Hojbjerg (Bowden 75), Dele, Bergwijn, Lucas (Lamela HT), Son (Scarlett 81).
Unused subs: Clarke, Cirkin.
Goal: Richards og (7), Alli (21), Son (42), Lamela (51)
Reading: Rafael (Southwood 82), Yiadom (Holsgrove 66), Richards (Samuels 82), Moore, Morrison (Holmes HT), McIntyre, Rinomhota (McNulty 86), Laurent (Araruna 81), Swift (Puscas 58), Olise (Meite 75), Joao (Baldock 58).
Unused subs: Aluko.
Goals: Puscas pen (80)