Frank laments unforgivable Tottenham defending in Burnley draw
Burnley were heading towards their first league win since October until Cristian Romero's 90th-minute equaliser salvaged a point for Spurs.
Micky van de Ven had put Tottenham in front during a dominant first half from the visitors at Turf Moor.
But Frank was enraged by the manner of Axel Tuanzebe's equaliser just before the break and Lyle Foster's second goal for the Clarets 14 minutes from time.
"We can never, ever, ever concede that goal just before half-time," said Frank.
"Second half was a bit more back and forth, we were not on top of it as much. I don't think we dealt well enough with that spell.
"Then we concede another bad goal, we can never concede. We should never be that open.
"Then we had a strong end with strong character with a lot of offensive substitutions to get the equaliser. We had three or four very big chances and scored one of them."
A point edges Tottenham up to 13th in the table, but they have won just two of their last 14 Premier League games.
A 2-0 victory over Borussia Dortmund in the Champions League on Tuesday had given Frank some breathing space after speculation his job was under imminent threat.
However, his position will come under more scrutiny with Spurs' hopes of European qualification for next season fading.
"The only way it can be is calm heads, carry on and keep doing what we think is the right thing," added the former Brentford boss on the rising pressure he is under.
"You see the game today. We do more than enough to win the game, we just need to defend better in two situations.
"And, of course, score another goal that could make the difference at 1-0."