Steve Borthwick said “these are painful days” after England’s 29-20 defeat by South Africa at Allianz Stadium stretched their losing run to five matches.
England started well but surrendered the lead twice before the world champions moved clear with Cheslin Kolbe’s second-half try.
Head coach Borthwick, whose side suffered a 2-0 series whitewash in New Zealand this summer before autumn home defeats by the All Blacks and Australia, said England failed to take their opportunities against the Springboks.
“I am incredibly disappointed and frustrated,” Borthwick told BBC Radio 5 Live.
“You see so much good, the way the team came out of the blocks at the start and came at South Africa.
“Then for a long time the game was toe-to-toe, but in the last period we failed to take our opportunities. How many times did we fail to take our chances in their 22?
“These are painful days. At times we are putting ourselves in positions to win games and we are not converting them. Whilst these are painful, we will use them in a positive way to help with our development.”
England have not won since June when they beat Eddie Jones’ Japan, who they face next in their final game of the Autumn Nations Series.
The hosts will be favourites to end their losing run and overcome their former boss and his Brave Blossoms, but Borthwick says his players have to learn from their experiences at Test level.
“We have a lot of young players that have come into this team and we have accelerated their transition,” he added.
“As you look towards the future these players are going to be brilliant international players, but right now these days of development are tough.
“We will persevere and be better because of these experiences.”
England had not lost three consecutive home matches since 2006 but Borthwick is confident he retains the backing of the Rugby Football Union (RFU).
“I’m not going to be talking about private conversations here, but what’s actually more important is the feeling I get,” said Borthwick.
“The feeling I get from the RFU is one of absolute support and absolute belief that this team is going in the right direction.”