Dover's impressive unbeaten record at Braintree came to an emphatic end in Tuesday night's Vanarama Conference clash.
Whites, unbeaten in their past three games at the venue, a statistic which included wins on their last two visits, lost 3-0 after being 2-0 down at the break.
Braintree, who finished sixth last season, opened the scoring in the 12th minute after centre half Alan Massey's shot beat goalkeeper Mitch Walker following Dan Sparkes' free-kick.
The home side doubled their lead 12 minutes later after a cross from Sparkes was missed by Dover defender Sean Raggett and James Mulley pounced to fire past Walker.
Dover Athletic's Mitch Walker
Walker then produced an excellent close range save to prevent Dover from going further behind.
Kinnear resisted making any changes at half-time but it wasn't long before he did, bringing on strikers Nathan Elder and Stefan Payne for Jake Reid and Barry Cogan in the 53rd minute.
Christian Nanetti then replaced captain Craig Stone, a move which saw Ricky Modeste switch to right back but there was no coming back for Dover.
Chris Kinnear jnr did have a shot from 25 yards which failed to trouble the home goalkeeper before Massey sealed Dover's fate when he headed home his second goal of the night from a Sparkes corner with six minutes to go.
Dover: Walker, Stone (sub, Nanetti 74min), Sterling, Kinnear, Raggett, Orlu, Wynter, Bellamy, Reid (sub, Elder 53min), Modeste, Cogan (sub, Payne 53min). Subs: Elder,Lock, Payne, Deverdics, Nanetti.