The 26-year-old won the prestigious event last season and was one of the favourites for this year’s race but was unable to finish after his FCC TSR Honda team-mate, Ryuichi Kiyonari, crashed in the third hour of the race. The damage sustained by the team’s CBR1000RR was too heavy to continue.
The Musashi team inherited the lead, which they extended to one lap over their nearest rivals and held it to the chequered flag, despite rain falling at Suzuka during the final, nerve-wracking 40 minutes.
Haslam, 30, whose father Ron was runner-up in the 1979 running of the 8-hours race, becomes the second British rider to win the Suzuka 8-hours in as many years after Rea’s victory last season.
Twenty-year-old Van der Mark, meanwhile, is the first Dutch rider to win the event, doing so on his first attempt and in his first competitive ride on a Superbike machine and his debut on Bridgestone tires.
Sunday’s victory, Honda’s 26th, was the fourth consecutive win for the CBR1000RR at Suzuka and its fifth in the last six years.
“This means so much after the tough season I’ve had,” Haslam said. “The leg held up pretty well during my stints but I just want to say thanks to the whole Musashi HARC-Pro team. They did a great job and also Mickey and Takahashi-san rode really well.
“I feel sorry for Jonathan and Kiyo [Ryuichi Kiyonari] but it’s a long tough race and anything can happen. I’m just glad that we managed to hold on to the lead until the end. It’s a really magical feeling.”
Yoshimura Suzuki's Takuya Tsuda, Nobu Aoki and Josh Brookes finished second on Sunday, despite a crash and a 30-second time penalty.
Team Kagayama - former World 500cc GP Champion Kevin Schwantz, Nori Haga and Yukio Kagayama - put its GSX-R1000 on the third step of the podium.
And making it three Suzuki GSX-R1000s in the top four of Japan's most-prestigious motorcycle event was reigning World Endurance Champions Suzuki Endurance Racing Team (SERT) with Vincent Philippe, Anthony Delhalle and Julien Da Costa taking the championship lead after two rounds.
Yoshimura Suzuki finished on the same 214th lap as the winners and also set the second-fastest race lap-time of 2:09.144. The fastest race lap of 2:08.827 was set by FCC TSR Honda's Kiyonari. Team Kagayama finished-up just one lap behind on 213, with SERT on 213, Yamaha France GMT94 on 212 and Honda Team Asia on 211 laps.
Yoshimura Suzuki's Tsuda, who started from second place on the grid, took the lead from the start from polesitter Katsuyuki Nakasuga (Monster Energy YART) and set the early pace until Nakasuga took over; and then Musashi's first rider on track, Takahashi, shortly afterwards.
Three hours in, Team Kagayama moved into second position as Aoki was given a stop-go penalty for allegedly infringing pit-lane speed; and then Brookes suffered a get-off. But the Australian held onto the bike, kept it running while picking it up ; and finished his full stint (one of four) - a move that earned him even more respect from the team and his new team-mates.
Yoshimura then fought its way back into second place ahead of Team Kagayama at the four-hour stage, a position the team held until the flag. As the rain started to fall and darkness closed-in, Yoshimura Suzuki stayed-out on track with its original tires and chose not to 'Pit' to change to Wets - as several other teams chose to.
"I went into the race as a first rider and I know this first hour is very important for the result,” Tsuda said. “Luckily I grabbed the holeshot but I was passed by Takumi Takahashi after about 40 minutes. Our bike, developed by Nobu Aoki mainly and myself with set-ups, was good and the Bridgestone tires were also good, but I couldn't use the hard tire for high track temperatures.
“I feel very frustrated to not able to win, but I also feel happy to be in second place for our team and our staff. I understand my weak points from the race and I would like to be a faster rider and return to the Suzuka 8-Hour next year."
Suzuka 8-Hour Results
1 Musashi RT HARC-PRO (Honda CBR1000RR) Takumi Takahashi/ Leon Haslam/ Michael van der Mark - 214 laps
2 Yoshimura Suzuki (Suzuki GSX-R1000) Takuya Tsuda/ Nobu Aoki/ Josh Brookes – 214
3 Team Kagayama (Suzuki GSX-R1000) Yukio Kagayama/ Kevin Schwantz/ Nori Haga – 213
4 SERT (Suzuki GSX-R1000) Vincent Philippe/ Anthony Delhalle/ Julien Da Costa – 213
5 Yamaha France GMT94 (Yamaha) Checa/ Foray/ Lagrive – 212
6 Honda Team Asia (Honda) Tamada/ Shah/ Kamaruzman/ Takahashi – 211
7 TOHO Racing with Moriwaki (Honda) Yamaguchi/ Ito/ Watanabe – 211
8 Monster Energy YART (Yamaha) Nakasuga/ Parkes/ Waters – 210
9 Honda Kumamoto Racing (Honda) Yoshida/ Kojima/ Tokudome – 208
10 Team R2CL (Suzuki GSX-R1000) Gwen Giabbani/ Masahiro Shinjo/ Dylan Buisson – 207
--From Pata Honda and Team Suzuki News Service