Bridewell and Easton battled it out in the early stages, the Quay Garage Honda rider getting the nod over the two-time race winner on lap ten, only for the youngster to slide out of the race when he lost the front-end at Graham Hill Bend.
Promoting Easton back to the third, the Scot was given no chance to rest as he came under attack from the recovering Seeley, the Relentless by TAS Suzuki rider giving the Swan Honda little room for error as they diced closely. Twice Seeley planted a move on Easton at Paddock Hill Bend, only for the pair to swap positions again on the run up to Druids, before he finally made the pass stick on lap 22.
From here, Easton, who is still nursing a knee injury, would begin to struggle as he got baulked by backmarker Steve Heneghan, allowing James Ellison through, before Brookes would edge past him too.
By contrast to his team-mate, Ellison was on a charge as he began to put pressure on Seeley, the 2009 runner-up eventually getting his man on lap 28 to snatch a strong podium finish from tenth on the grid.
Seeley held onto fourth, ahead of Brookes, the Australian slipping back by the chequered flag but safe in the knowledge his fastest lap will ensure he starts on pole position for the second race.
Easton eventually slipped back to sixth, ahead of Michael Rutter, who enjoyed an uneventful, but impressive run to seventh, the recovering Linfoot, Chris Walker and John Laverty.
Outside the top ten, Martin Jessopp was 11th on the second Ridersmotorcycles.com Ducati to finish in front of Yukio Kagayama, who gradually faded to 12th, 26secs behind his race winning team-mate.
Having started at the back of the grid, Gary Mason secured three well earned points on his Kawasaki debut in 13th, while Steve Brogan became the first rider to win an Evo race in 14th overall. Peter Hickman scored the 15th and final point.