A record crowd, sizzling temperatures, scorching racing – Snetterton marked round six of the British Superbikes Championship in style.

More than 43,000 spectators crammed into the Norfolk circuit during the weekend, the first headline event for its new Snetterton 300 format. And the racing did not disappoint, with two thrilling superbike (BSB) contests that went all the way down to final-lap tangles.

American title challenger John 'Hopper' Hopkins marked Independence Day early with arguably the best of things, taking a sweet race-one victory on his Crescent Racing Suzuki from Tommy Hill's Swan Yamaha – just as Hill looked set for his third win in three races.

Hopper then seemed a certainty for top step in race two – only for his battle with championship leader Shane 'Shakey' Byrne to ultimately push the pair into mistakes.

Hopkins forced Byrne off the track before losing traction and places, letting in defending champion and Byrne's HM Plant Honda team-mate Ryuichi Kiyonari for the win.

Hopkins did at least hold on to third behind Relentless Suzuki's Josh Brookes.

'The race win was ours to loose in race two and I had led pretty much every lap,' said a disappointed Hopper. 'Nobody was giving any room out there but it was good close racing that the fans want to see.

'I was disappointed I didn't do the double as I felt we could have won both races. I am racing for the championship though and Shakey is my main opposition, so I was always going to try and get ahead of him and was giving it everything as always.

'I have apologised to Shakey but I think everyone can see we both wanted that win.'

Kiyonari added: 'I am of course happy for the win and I was lucky as I could have been third rather than first. I am sorry for Shakey and John but we needed the win here for our championship, especially after some bad results. Our hard work has finally paid off.'

Post-race thoughts were also with Steve Brogan and Simon Andrews after a horrific race-two smash left the pair in a bad way.

Midway through the race Alex Lowes' MSS Colchester Kawasaki mechanical failure at Riches left fluid on the corner – enough to send Brogan into the tyre wall with Andrews skidding across the run-off area close behind and two Superbikes flying 40ft in the air.

Brogan eventually came to with a shoulder injury but Andrews was not so lucky, leaving with a double break to his right leg. The new Montreal hairpin and Oggies also caused problems as riders got to grips with Snetterton's mammoth new format.

A thrilling BSB opener saw pole-sitter Hopkins lead from the front, while Byrne was quickly on a charge after his qualifying issues – and tantrum – up to third from sixth within the opening lap of 17.

Team-mate Kiyonari was doing likewise before the safety car bunch things up thanks to Tom Tunstall's nasty flip and Hudson Kennaugh's blow out.

The lap nine restart saw Hill pounce from second, making the most of Hopkins' wide at Agostini – with Byrne following through at the end of the Bentley straight.

But Hopkins was not having any of it. His Crescent Racing Suzuki was back ahead of Shakey by the time they reached Riches, and the former Moto GP man's pressure on leader Hill finally told on an exhilarating last lap – sharing the lead before Hopper held on around Corum for the second win of his debut season.

While the new Snetterton layout has attracted rave reviews, BSB veteran Michael Rutter was a willing voice of dissent – claiming the three-mile format was 'like a go-kart track'.

Whether a disappointing 13th race-one finish on his Ducati had anything to do with Rutter's feelings was a moot point – his second race ended in the pits after less than a lap.

At the front, Hill's hopes to go one better came to an end after three corners. Kiyonari and Hopkins went wide battling at Montreal, leaving Hill with nowhere to go.

The lap eight red flag effectively left a nine-lap shoot-out for the win – and Hopkins was quick-sharp off the line again.

But Byrne hassled the San Diego man all the way, and an audacious move at Corum sent Shakey through.

Hopkins' retaliation came a lap later, but pushed Byrne off the track and ultimately handed Kiyonari the win.

Aussie Brookes' second saw him in the prized top six: sit there after round nine and you are handed a title shot with seven races to go. Hopkins, Byrne, Kiyonari, Hill and team-mate Laverty join Brookes in the elite group heading out of Norfolk, but the battle is far from over.

• British Superbikes (round six, Snetterton) – Race One: 1 John HOPKINS (USA, Samsung Crescent Racing), 2 Tommy HILL (GBR, Swan Yamaha), 3 Shane BYRNE (GBR, HM Plant Honda). Race Two: 1 Ryuichi KIYONARI (JPN, HM Plant Honda), 2 Josh BROOKES (AUS, Relentless Suzuki), 3 John HOPKINS.

• Current standings: 1 Shane BYRNE (Honda) 201 points, 16 podium credits; 2 John HOPKINS (Suzuki) 182, 15; 3 Tommy HILL (Yamaha) 140, 13; 4 Ryuichi KIYONARI (Honda) 120, 8; 5 Michael LAVERTY (Yamaha) 119, 4; 6 Josh BROOKES (Suzuki) 91, 2.