Back strike — a rise is most important (9)

I haven't cracked this one yet — but the brilliant team at Fifteensquared have:

reversal of RAP [strike] + A + MOUNT 10 USAGE : U[niversity] SAGE [man of learning] 11 COD WARS : cryptic definition, referring to the fishing disputes of the 1950s and 1970s 12 LOBELIA : OBELI [daggers] in reversal of AL [Capone] I liked this one 13 LATER : anagram of ALERT 14 FIG LEAVES : a witty cryptic definition [not quite ‘first-day’, if we want to be picky!] 16 TERRITORIAL ARMY : cryptic definition 19 REINFORCE : REIN [check] + FORCE [power] 21 SEPIA : I [one] in reversal of APES [copies] 22 HUMERUS : HUM [throbbing] + reversal of SURE 23 DUNKIRK : DUN [dingy] + KIRK [church]: I thought ‘place in British history’ was a rather loose definition 24 LOTTO : LOT [a great deal] + TO: I didn’t think there was a great deal to this clue but I suppose we were intended to suspect it was a card game 25 EYE STRAIN : EYES [monitors] + TRAIN [public transport]