Scorer getting runs after live game's start (4)

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

R (runs, in cricket scoring) after BE (live, as a verb), then the starting letter of G [ame]. The surface suggests a somewhat better cricket performance than in 29a, but the “scorer” here is actually a composer of musical scores: the Austrian composer Alban Berg.