Cryptic crossword No 4,084

Across

1. Face vessel - one with much 10? (3)
2. Abandons in deep 27s (7)
3. Little guy in boat race quietly passed and 1 21 won it (3,5)
4. Imprisonment is part of toxic US to dying (7)
5. See 12ac
6. Sad city blokes part of database (10)
7. See 11dn
8. Strange willingness to accept perversely dirty clue (9)
9. Part of Rio's a Kazakh city with Asian residents (5)
10. Let adults only win about 50-50 (5)
11. See 1dn
12. State to quash Miami photo finishes (4)
13. Who's rock opera would sound before one crows in the morning for final trainer with 1 21? (5,8)
14. Fills in as new first in line in rowing team before finals of the qualification races (10)
15. Quickly write about popular venue (5)
16. Bird 5 mostly scrambled for 1 21 (3,3)
17. Taking in me, down and out guy, unknown, is being a member of my community (7)
18. Nasty scare in substance that might have killed 1 21 (7)
19. Minor 11 almost gets Ashes trophy, turning purplish 27 as... 1 21 won it! (9,3)

Down

1. See 19ac
2. See 16ac
3. Animal with pathogens in heart (3)
4. See 30ac
5. See 25dn
6. Minion, at heart, feels too gentle (6)
7. Not told of "neutral" invading wearing military outfit (10)
8. Who was usually on top of 1 21? Judge and one politician: Eisenhower (3,4)
9. Steer south of black hedge (3)
10. Coat for truck (3)
11. Performs better in "Spring Carnival" perhaps, but joust ruined with official involved (8)
12. 12 down might have one, or 51,500 (3)
13. Vessel of rum? Belt loosened! (7)
14. Some bloke rode sheep and wears down (6)
15. Fresh enthusiasm and 1 21 came from here (3,7)
16. See 14dn
17. Rough accommodation for the 15 down - no alternative in this story? (3)
18. Arterial busy and chaotic, a Sydney race and 1 21 won it! (10,5)
19. Wonder horse with firsts in pretty hard arse races, lastly annual Tijuana handicap (4,3)
20. Estate's last horse... good source of protein? (3)
21. Where many runners are from, some seeking to return (4)