The home form that saved Derby County from relegation last season deserted them as Leicester City shaded a keenly fought East Midlands contest at Pride Park.
An excellent defensive display from the visitors was the platform for a victory that was sealed when substitute Trevor Benjamin scored with his first touch 14 minutes from time.
The result was harsh on Derby who showed plenty of spirit, but once again their failure to take chances proved costly.
An awful miss by Tommy Smith proved the turning point a minute before Lilian Nalis gave Leicester the lead, with a shot that appeared to bounce twice through a crowd of players.
Although Marcus Tudgay headed an equaliser, Benjamin punished Michael Johnson's first mistake of the game to give Micky Adams his first win of the season.
Derby can at least look back on some excellent approach play and an impressive performance from teenager Tom Huddlestone who was composed alongside Johnson in the heart of the defence.
But Leicester, with Martin Keown outstanding, restricted the home side to a few half-chances before Smith blazed over from ten yards in the 40th minute.
When Nalis struck, Derby were in trouble and they could have been sunk when Jeff Kenna barged into Gareth Williams to concede a 56th minute penalty.
However, Lee Camp dived to his right to deny David Connolly who then sliced the rebound over the bar and Derby had the chance to salvage something from the match.
Tudgay equalised in the 69th minute when he headed in a Morten Bisgaard corner from six yards, but Adams came up trumps with a triple substitution five minutes later.
Derby were caught by Ian Walker's long ball which Williams headed on, and Benjamin turned Johnson before lashing a left-foot shot into the bottom left-hand corner of Camp's net.
Derby almost drew level again when Huddlestone volleyed against the bar from the edge of the area, but Ian Taylor could only hook the rebound wide.