Head coach Eddie Jones refused to be drawn on the controversial decision which denied England a memorable win over New Zealand at Twickenham on Saturday.
Jones said: “I don’t comment on those decisions. I’ll leave it up to that guy. If he can’t take the right decision with 10 replays, who can?
“Sometimes the game loves you and sometimes the game doesn’t love you. We’ll get some love from the game further down the track.”
New Zealand head coach Steve Hansen said: “There was no doubt he’s offside. What was going through my mind was are they going to be brave enough to make the right decision? And they were.”
Underhill told BBC Radio 5 Live: “I don’t know what I was thinking when I went over.
“I wasn’t watching the screen. At times like that we don’t watch the decision, we look to the next job.
“When it got brought back it was what it was but it’s those small margins.”
It was a first meeting between England and New Zealand in four years and many expected the All Blacks to trounce their injury-depleted hosts.
But afterwards it was Jones who insisted England were on course for World Cup glory after the agonising defeat.
Beauden Barrett’s penalty saw New Zealand take the lead for the first time in the game after 60 minutes and they did not relinquish it.
Jones accentuated the positives and looked ahead to next year’s World Cup in Japan.
“We’re disappointed, but we’re excited about where we’re going,” Jones added.
“We’ll learn a lot from that today. We had opportunities to win the game, we didn’t take them, they did. They deserved to win the game.
“It’s a really good step forward. You benchmark yourself against New Zealand. New Zealand are the best team in the world.
“We’ve got to fix the things that didn’t work today. If we do that, we’re on the road to being the best team in the world, which is what we set out to be.”
Jones felt England were in the ascendancy in the final quarter, when a drop goal opportunity failed to materialise.
“I thought we played the final 20 [minutes] exceptionally well,” Jones added.
“That’s where New Zealand generally run away from teams and they couldn’t. They couldn’t break us.
“If we’d kept going for another five minutes, we maybe would’ve got them.”
Hooker and co-captain Hartley went off at half-time with a thumb injury he has been carrying, while lock George Kruis has a calf problem which will be assessed.
New Zealand’s influential centre Sonny Bill Williams went off with a shoulder injury in the first half.
The All Blacks won the World Cup on their most recent visit to Twickenham, in October 2015, when England became the first hosts to exit at the pool stage. They have been transformed under Jones, who was appointed in December 2015.
Hansen said: “He’s doing a good job here for England. Last time we were here was 2015 and things didn’t go that well for England.
“Since then they’ve won 18 in a row, they’re in the right place.
“They’ve showed today they’re going to be competitive against whoever you want to play against them.”
Hansen, though, had words of praise for his side too.
He added: “I thought England were very, very good and I thought we showed a lot of character.”