Glasgow Tigers go head to head with Edinburgh Monarchs twice this weekend in what Scottish speedway bosses say are some of the most important derbies of recent seasons.
Tigers face the Monarchs at Armadale on Friday before the return at Ashfield on Sunday, going into the fixtures with virtually identical league records.
Both are chasing a top-four place to make the end-of-season play-offs - and it could come down to a straight shootout between the Championship's only Scottish sides for the last remaining spot.
The meetings have added spice in the fact that five riders will face their former clubs - Craig Cook, Richie Worrall, Claus Vissing, William Lawson and Victor Palovaara.
Glasgow man Cook only rides on Sunday as he's practising for the Polish Grand Prix on Friday - but former Tiger Ben Barker steps in as a guest.
Cami Brown, Tigers manager, said: "The derby is always special but few have mattered more than this weekend's.
"There are headlines ready to be made everywhere - riders facing their former teams, the potential to put a huge dent in each other's play-off hopes, and loads of rivalry on the terraces.
"Cookie being missing tomorrow is a blow but Ben is a great lad, he loves riding for the Tigers, and he'll be as fired-up as anyone to score big points. Craig returns on Sunday to face the club he won so may trophies for and that in itself will be worth watching.
"Then you have four other riders facing the teams they used to ride for - they'll all have points to prove.
"And on top of that, both clubs are desperate for points on the road to help them make the top four, so the results really are crucial.
"We know we can win at Edinburgh, we did it earlier this year, and it's very much our aim to pick up points there.
"But I think both meetings will be ultra competitive and for the neutral - though there won't be many - it will be a treat to watch."
Nathan Greaves will also be in the Tigers line-up as he continues his comeback from injury.
Friday's meeting starts at 7.30pm with Sunday's fixture starting at 3pm.