Matthew Mott and Jos Buttler have agreed England's Twenty20 International series defeat to South Africa was "a line in the sand moment".

Mott was recently appointed England's new limited-overs head coach, with Buttler newly installed as white-ball skipper.

But the pair have not enjoyed the sort of strong start seen in the Test arena under Brendon McCullum and Ben Stokes.

England lost ODI and T20I series' to India, both 2-1, before facing South Africa.

A three-match ODI series was drawn, but Buttler's men then let slip a 1-0 lead in the T20Is to lose again.

England looked to be on the right path with their opening 41-run win, only for subsequent reverses by 58 and 90 runs to prompt serious concern.

Following that latest dismal defeat, Mott was not shying away from the need for vast improvement.

"I've just spoken to Jos very briefly, and this is a line in the sand moment for the team," the coach told Sky Sports.

He added: "We were down on confidence with bat and ball. It was disappointing.

"I thought we put ourselves in a good position to win the series, and we'll have take a lot out of that game."

This sequence of underwhelming results comes ahead of a T20 World Cup at the end of the year, too.

"It's been a bit of a struggle," Mott told BBC Sport. "We've had ups and downs throughout the summer.

"We've played two great teams and come out second both times, so we're disappointed."