Greul is past it though, time for him to retire, like you said he was top 100 2 years ago. Pella has been kinda crappy lately.
Simon has had a very good second half of the season this year. He was hurt and sick much of last year. It took him time to find his game but he's gone from out of the top 200 to potentially in the top 130 if he wins the challenger this week. He's headed back to the top 100.
Losing to Greul isn't a bad mark on Pella.