Although not presented in the "jigsaw" format, this is an "alphabetic" puzzle, in the sense that there is exactly one solution starting with each letter of the alphabet...

   7. An Agassi with a Bocelli (6)
   9. Mary lied ridiculously, as if in a fantasy (8)
  10. Some give up on capturing soldier before end of day (8)
  11. Attraction breaking rules about time (6)
  12. Not in tune, said organisation? (6 7)
  14. Had puppies provided assistance, would leader have front spot? (7)
  16. Big semi crashed with fellows inside (7)
  19. Catastrophic end over temple rebuilding? (13)
  22. Jelly wrestle involving King and Doctor (6)
  24. Going without second sleep (8)
  25. Island country's returns in TAB: is risk utterly pointless? (8)
  26. Bohemian Mahler a breath of fresh air after Viennese leaders (6)
   1. Following ideal practice, public relations incorporated form of online address light on hardware (10)
   2. Islanders to exist in surrounding saline solution (8)
   3. Talking horse passing on in rapid fashion? (7)
   4. One overly eager to laze about? (6)
   5. Famous uncle cross having to come back as holiday cut short (4)
   6. Harris turned, and is about devious ends they arrange (8)
   8. Island country's run to ruin accommodating Australia (5)
  13. Make them seen too much and see poor vex management (10)
  15. Meet rich lunatic, really tight (8)
  17. Mathematical functions in cartographic processes? (8)
  18. Leaders of culture learn about such stuff in college (7)
  20. God can divulge heart first (6)
  21. Island country's got an issue (5)
  23. Norse character returns, filthy, headless (4)