Fresh off his against-the-odds triumph in Super Formula last weekend, Kiwi star Nick Cassidy finds himself chasing another title as he aims to overhaul the championship-leading LeMans LC500 of Kenta Yamashita and Kazuya Oshima.

At stake is the rare chance of winning Japan’s two biggest series in the same calendar year, something no ‘gaijin’ racer has achieved since Richard Lyons in 2004.

Of course, Naoki Yamamoto did complete the double last year - incidentally by beating Cassidy in both championships - but it would truly be remarkable for a foreign driver to achieve the same feat against homegrown Japanese racers.

Cassidy is an established figure in SUPER GT and he and TOM’S teammate Ryo Hirakawa make one of the most exciting pairings in the series’ premier GT500 class.

Together the two clinched the 2017 title - becoming the youngest driver duo to do so - and again fought for top honours last year, before narrowly losing out to Yamamoto and Jenson Button in a crunch finale.

Cassidy and Hirakawa’s 2019 season got off to a rocky start as they finished outside the points in a rain-shortened Okayama race, but since then they have catapulted themselves to second in the standings with three podiums in the last six races.

Race winners: #6 LeMans Lexus: Kazuya Oshima, Kenta Yamashita Photo by: Masahide Kamio

However, overturning a seven-point deficit will be no easy feat, especially as they are up against a very strong pairing in Yamashita and Oshima, who have exceeded all expectations in what was supposed to be a rebuilding year for Team LeMans.

The Lexus squad lost its much-loved race engineer Kenji Yamada in tragic circumstances at the start of 2018, and had to rejig its engineering workforce to fill in for his absence.

But the outfit has managed to emerge from the shadow of that tragedy much earlier than expected, taking an emphatic victory at Buriram - its first in six years.

Yamashita and Oshima then won again at Fuji after strategically pitting just before a safety car period, the bonus points scored building the foundation of their current championship lead over the TOM'S Lexus of Cassidy and Hirakawa.

Should Yamashita and Oshima clinch the crown, it will mark LeMans' first title since 2002 - when the series ran under the All-Japan Grand Touring Car Championship (JGTC) moniker.

It will also vindicate Toyota’s decision to field Yamashita in the LMP2 class of FIA World Endurance Championship, having stopped the practice of giving international breaks to sportscar drivers since Yuji Kunimoto’s underwhelming Le Mans 24 Hours outing with its LMP1 squad in 2017.

Podium: second place #37 TOM'S LC500: Nick Cassidy, Ryo Hirakawa Photo by: Masahide Kamio

What makes the rivalry between the two Lexus teams even more exciting is the fact that they’ve had two notable on-track battles this season, with the score currently level at 1-1 each.

Cassidy and Hirakawa got the upper hand at Suzuka as they fought for second place, before Yamashita and Oshima resisted advances of their rivals to seal victory at Buriram.

This time however, merely finishing ahead of Yamashita and Oshima may not be enough for Cassidy and Hirakawa to clinch a second title in three years.

Even if the TOM'S pair win at Motegi, they would need Yamashita and Oshima to finish third or lower to secure their second title in three years.

Conversely, if Cassidy and Hirakawa fail to finish inside the top four, the title will automatically fall in the hands of the LeMans pairing - and Yamashita and Oshima's two wins would result in them winning the title on countback if both crews end up level on points.

How Cassidy and Hirakawa can win the title:

If Cassidy/Hirakawa finish... ...Yamashita/Oshima must finish no higher than: 1st (with or without pole) 3rd 2nd (without pole) 4th 2nd (with pole) 5th 3rd (without pole) 7th 3rd (with pole) 8th 4th (without pole) 10th 4th (with pole) 11th 5th or lower Yamashita/Oshima win the title

Nissan's factory-entered NISMO outfit may practically be out of title contention, it still has a mathematical chance of stealing the title from the two Lexus squads.

However, to do so, Ronnie Quintarelli and Tsugio Matsuda must not only grab pole position and win the race, they must also hope Oshima and Yamashita fail to score, as they are 20.5 points behind the LeMans crew with only 21 on offer.

Even so, Quintarelli and Matsuda could well fight for the win at a track they’ve enjoyed plenty of success in the past, with two victories in the last five years.

Motegi also marks the swansong SUPER GT outing for ex-Formula 1 world champion Button, who will be calling time on the Japanese series after two seasons.

Button’s presence in the series has been thoroughly embraced by all those in the SUPER GT paddock, and the Englishman’s title success in his rookie season alongside Yamamoto went a long way in boosting the international profile of the series.

Their title defence has proven to be much tougher - and the pair will be doubtless be keen on ending their partnership with at least a podium, if not a victory.