Tommy Wright was satisfied that his plan for St Johnstone to knock Rangers out of the League Cup came to fruition as the Perth Saints won 3-1 at Ibrox.
A clever move rounded off by Murray Davidson, an 18-yard strike by Simon Lappin and a goal by Michael O'Halloran put St Johnstone firmly in control.
"It was a perfect first half for us. We came with a plan," said Wright.
"I thought playing Mikey (O'Halloran) up top would cause them problems and that proved to be the case."
Rangers rallied and pulled a goal back from a fierce James Tavernier shot but they could not sufficiently trouble Alan Mannus's Saints goal and their 11-game winning run was ended by the Premiership team.
St Johnstone's second goal came from a corner, with David Wotherspoon passing directly to the unmarked Lappin at the edge of the box. His first-time strike could hardly have been sweeter.
Wright continued: "We'd worked on set plays. It's always nice when something comes off. We thought that was an area we could exploit. We had worked on that yesterday.
"To be 3-0 up within 46 minutes was incredible for us.
"If he gets it right, Michael can cause anybody problems because he's got real pace. He's always a good outlet for us and he always keeps the two centre-halves occupied.
"Rangers had a right go, even at 3-0. We were under a lot of pressure.
"We defended really well and didn't give them many opportunities. I am really pleased with how things went."
Saints skipper Dave Mackay admitted Rangers "were running over the top" of his team for the first 15 minutes but thereafter felt they were worthy winners.
"Not many people would have thought we'd come here and win, given the form Rangers have been in and the form we've been in, which has been patchy," he told BBC Scotland.
"But in that dressing room we know how good we are when we play that way."
For Rangers manager Mark Warburton, it was his first defeat of his short tenure, but the former Brentford boss promised the team will learn from the Cup exit.
He said: "Credit to the opposition. They came with a game plan and they got their rewards in the first half. They showed pace up front and we gave a couple of silly goals away.
"I thought we stuck to the task. Tonight wasn't our night.
"Last year [at Brentford] we had one bad half of football away and we referred to it all season. That could be the equivalent here, We will learn from that first half.
"We have been together since June 27, less than three months, with 11 new players.
"The players' application has been outstanding. We are not in bad shape."