Colin Tizzard admits Thistlecrack's season-ending injury "hit me for six".
Speaking at a press day at his Dorset yard, Tizzard accepted he is still coming to terms with the fact his brilliant nine-year-old will not run in the Cheltenham Gold Cup next month.
Thistlecrack was the ante-post favourite for the race, but was on Tuesday ruled out for the remainder of the campaign with a tendon injury.
"When I saw him on Tuesday morning, it was not great at all," said Tizzard.
"We scanned him, and the realisation he was out hit me for six.
" I thought I was stronger than that."
The long-term prognosis for Thistlecrack is positive, though, with his trainer already plotting a return to Kempton over Christmas for a repeat bid in the King George VI Chase.
Tizzard said: " The good part about it is you could walk into the stables now and not know what leg it is (he injured).
"We've got to enjoy what he's done this year and hopefully we'll get him back for Christmas, and hopefully he can do it all again.
"We trotted him out (Thursday morning) and he was sound as a pound. It's not life-threatening.
"He's only out for the season, so we've got to move on."