The Olympic bronze medallist cleared 2.31 metres to win by nine centimetres and only narrowly failed to beat Steve Smith's 19-year old British indoor record, with a close attempt at 2.39m.
"I've never had the indoor title so that was my target and then come in and try to get the world lead," said Grabarz.
"It wasn't too bad but I was just running too fast so it was the same story as always. It was only my second competition so to be jumping that high is pretty good.
"I'm ready to try and break the record. I've been training hard, I've not done too many competitions indoors so I know that when I come out I'm ready to go and showed that."
Nigel Levine overcame the challenge of Richard Strachan and Michael Bingham to win the 400m, his third career national title, in a season's best 46.73 seconds while Margaret Adeoye held off the challenge of 400m specialist Christine Ohuruogu to win the 200m in 23.22 secs.
In former Olympic champion Ohuruogu's absence, Eilidh Child beat Olympic 400m semi-finalist Shana Cox to win her first UK indoor title over 400m, clocking 52.13 secs.
"I'm over the moon, I just wanted to win it. I've had so many silvers at UK Championships before so it's great to finally get a gold," said Child.
"It's been a great weekend for me. I was a bit worried about how I'd run after having a hard run last night. I'm happy that I've came out and done two solid races back to back."
Yamile Aldama is upbeat about adding the European indoor title to her world indoor crown after winning the triple jump with a 13.44m best, while Steve Lewis won the pole vault with a 5.50m clearance.
"It feels good to defend the title, winning is always good," said Aldama, who finished fifth at last year's London 2012 Olympics.
"I wasn't happy with the distance, but I'm coming back slowly after the surgery that I had at the end of September. Training is going really well though.
"I think I will be fully fit for Gothenburg. All that matters there is that you deliver on the day."
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