"We still don't know if he's an elite marathoner."
He's the first American to win the race since 1982.
He was the 10th ranked starter in the elite field, by time:
Dennis Kimetto KEN 2 2:02:57
Stanley Biwott KEN 3 2:03:51
Feyisa Lilesa ETH 4 2:04:52
Abel Kirui KEN 1 2:05:04
Sisay Lemma ETH 5 2:05:16
Ezekiel Chebii KEN 6 2:06:07
Bernard Kipyego KEN 7 2:06:19
Kohei Matsumura JPN 9 2:08:09
Galen Rupp USA 10 2:09:58
He beat Kimetto (WR holder), Biwott, and Lilesa. Lemma couldn't handle him. He completely dominated last year's winner, Kirui--just ground him down to paste the moment he put the hammer down. Kirui was lifting and bouncing like a frog; his stride shot to pieces, basically. And Rupp just motored on at 4:32 pace (something like that) for the last three miles.
I'd call him an elite marathoner.