VIDEO: Ackermann praises Sale's X-factor Boks
Twelvetrees kicked Gloucester to a narrow 20-16 victory over Sale in a tight match at Kingsholm.
The lead changed several times with Sale's AJ MacGinty scoring all of his side's points.
However, it was not quite enough as David Halaifonua and Ben Vellacott went over for Gloucester's tries – with Twelvetrees kicking 10 points.
Ackermann admitted it was not pretty and there are plenty of work-ons.
He said the West Country outfit need to improve drastically if they are to make the best of their current top-four position in the Premiership.
"We will reset, going into 2018 with the ambition to keep improving," Ackermann said in his post-match reaction.
The South African also had some praise for Sale's star players – centre Rohan Janse Van Rensburg and scrumhalf Francois de Klerk, who became Springboks while playing under him at the Lions in Johannesburg.
While Gloucester's South African contingent included just Ackermann and his son Ruan, Sale had double that in SA players.
Janse Van Rensburg, De Klerk, No.8 Josh Strauss (a former Lions captain and now a Scottish international) and Bulls loose forward Jono Ross.
"They are good players," Ackermann said, when asked about the influence of De Klerk and Janse van Rensburg on the game.
"Faf showed his experience," the Gloucester coach said, adding: "He knew when to put the pressure on around the rucks and created a great try.
"Rohan is always strong with ball in hand.
"That is what you get, in every team – there are those X-factor players.
"Lost of the game we contained them well.
"The most disappointing thing is we didn't treasure the ball enough and at times our discipline, again, cost us momentum."
Ackermann also said that finishing the calendar year in the top four of the Premiership will mean nothing if they let their promising position slip in 2018.
"It's a nice place to be but it brings other challenges as well," Ackermann said.
"One must be grateful that this is where we are at the end of 2017 but saying that there are still four or five months of tough games ahead and it will mean nothing come mid-2018 if we let it slip.
"We must stay in the moment, enjoy this victory but also know there's a lot of hard work ahead come the new year."
