Fifteensquared

I don’t recognise the setter’s pseudonym so it is either a new contributor or a rebranding of an existing one for the purpose of this tennis related puzzle.

Nothing particularly difficult today though I was held up briefly by having initially entered ‘tennis court’ at 9d (for a change I decided to tackle the clues in reverse order so didn’t have any checked letters and hadn’t seen 5d).

Across
7 EMERSON  REME (engineers) reversed SON (lad) – Roy Emerson, Australian tennis player from the ’60s
8 SOLOMON  SOLO (alone) MON (early in the week)
10 BASELINE  BASE (camp) LINE (actor’s words)
11 DEFEND  DEF[ected] END (finish, homophone of Finnish)
12 BLEAT  L (a number) in BEAT (thrash)
13 STEEL BAND  homophone of ‘steal’ (nick) ’banned’ (can’t join the group)
16 DOUBLE-FAULT  cd
19 SENSATION  *(AS TENSION)
20 SPARK  SPAR (pole) K[rakow]
22 INDIAN  *(DIN) IAN (a Scotsman)
24 REPORTER  RE (about) PORTER (beer)
25 ATHLETE  *(THE LATE)
26 ALSO RAN  hidden in ‘terminAL SO RANk’

Down
1 AMIABLE  AM I ABLE (can I)
2 FREEMASONS  *(RANSOM FEES)
3 TOPIC  OP (operation) in TIC (nervous twitch)
4 GOLD MEDAL  cd
5 ROOF  cd
6 JOINING  IN IN (double in) in JOG (trot)
9 CENTRE COURT  cd
14 BALL PERSON  cd
15 OBSTINATE  *(SOB) TIN (metal) ATE (consumed)
17 KEYNOTE  KEY (a minor, for example) NOTE (write)
18 ARSENAL  AR[e] LANES (streets) reversed
21 APPLE  A PP (very quiet) LE (the, in French)
23 IDLE  hidden in ‘morbID LEthargy’