Coates, who started from pole position, was challenged by Young early on and needed to bravely hold on around the outside line at Paddock Hill Bend to retain the lead on the lap three.
From there he drew clear but in the closing stages Young closed back in and at the chequered flag was only 0.351s adrift of the Team HARD driver.
Coates, who also took bonus points for leading the race and setting the fastest lap, reflected: “The move around the outside of Jack at Paddock decided it. The outside line there works in the wet and he showed great respect by leaving me just enough room.
“After that, maybe he didn’t work his tyres quite as hard as me which is why he came back towards me but I felt in control – although he was pretty close on that final lap!”
For Young, second place marked his first podium result in the UK Clio Cup. The 17-year-old said: “That was a really good battle with Max at Paddock – we showed each other respect which is how I like to go racing. I’m quite happy with second place – it’s points in the bag – but of course I wanted the win. I didn’t know it was the last lap – otherwise I’d have had more of a go!
Young’s own MRM team-mate Lidsey finished an almost identical amount ahead of HARD duo Ethan Hammerton and Jade Edwards to take third place.
Lidsey briefly got ahead of Young for second early on before slipping back and becoming embroiled in an intense battle with Hammerton and Edwards for the final podium position. Hammerton got ahead with a move into Surtees Bend but, at Paddock Hill Bend the next time around, Lidsey was able to re-assert himself with a demon move under braking.
Despite the pressure from behind he was able to hold off Hammerton and Edwards who still celebrated personal best results (Hammerton on his debut) of fourth and fifth.
Lidsey said: “My car was very strong in the first few laps but after that it developed understeer so it was a case of hold on and hope for the best. To get my first podium after such a hard battle and at my home track is a great feeling.”
There was an equally exciting battle for sixth which eventually fell the way of Westbourne Motorsport’s Aaron Thompson, also achieving his best result to date. He had to work hard to resist team-mate Finlay Robinson who took a fine seventh on his debut.
This pair were followed across the line by R-Tech Welding/MRM’s Ben Davis and Westbourne’s Ben Colburn in a four-car train that was covered by just over a second.
Specialized Motorsport’s Luke Warr completed the top ten but there was frustration for Anton Spires who was unable to start when his Westbourne car struck mechanical problems on the grid.
Result: Round 1, Brands Hatch Indy
1. Max Coates (Team HARD), 19 laps in 18m53.152s (72.91mph)
2. Jack Young (MRM), +0.351s
3. Brett Lidsey (MRM), +10.344s
4. Ethan Hammerton (Team HARD), +10.908s
5. Jade Edwards (Team HARD), +11.262s
6. Aaron Thompson (Westbourne Motorsport), +20.711s
7. Finlay Robinson (Westbourne Motorsport), +21.032s
8. Ben Davis (R-Tech Welding/MRM), +21.200s
9. Ben Colburn (Westbourne Motorsport), 21.998s
10. Luke Warr (Specialized Motorsport), +41.203s
Fastest lap: Coates, 58.808s (avg. 73.94mph)
1. Coates, 28
2. Young, 22
3. Lidsey, 20
4. Hammerton, 18
5. Edwards, 16
6. Thompson, 13
7. Robinson, 10
8. Davis, 8
9. Colburn, 7
10. Warr, 6