Andoni Iraola completely dismantled Erik ten Hag's tactics following Bournemouth's big win over Manchester United on Saturday.
The Cherries smashed Man United 3-0 at Old Trafford as Dominic Solanke, Philip Billing and Marcos Senesi all got on the score-sheet.
Ten Hag's reaction following the final whistle was a telling moment while captain Bruno Fernandes addressed the boos at full-time.
Bournemouth, meanwhile, are now unbeaten in five league matches and climb to 13th place in the Premier League table.
Iraola, who was appointed in the summer, not only guided the South Coast outfit to their first-ever victory at Man United, but is also starting to work his managerial magic, having earned a stellar reputation in Spain's La Liga.
And speaking after the result, the 41-year-old ruthlessly dismantled Ten Hag's tactics against his side.
He explained why how his team were able to score three goals as he exposed the Dutchman's playing style.
"They send a lot of players forward so you will get spaces," said Iraola via Utd District.
"In this kind of open game when you know there will be chances for both games, we spoke at half-time and needing more goals if we want to win."
The Spaniard added: "When you send so many threats, it’s a matter of numbers, you have situations to attack 2-v-2, 3-v-2, 3-v-3, we were good in these moments.
"We knew they would make our wingers run backwards, but we knew when we could recover high, our forwards would have space.
"We knew in transitions we would have our chances and we took them."
It's back to the drawing board for Ten Hag, who will prepare his side for games against Bayern Munich and Liverpool next week.
They face the German giants in a crunch Champions League clash before travelling to Anfield next Sunday to face the league leaders.