Lincoln's Ben House gave his side the lead in the third minute of the game.
Newly promoted Lincoln City comfortably beat fellow Championship side Derby County to reach the second round of the Carabao Cup.
First-half goals from Ben House and Dom Jefferies were enough to give the Imps the win, with the home side struggling to create anything meaningful in front of goal.
After re-signing from Ipswich Town on loan with an obligation to buy, Sammie Szmodics gave Derby a lifeline as he found the top corner with a volley from 30 yards out in first-half stoppage time.
Lincoln started the second period in the ascendancy, as House came close to adding a third goal, but his shot was deflected into the side netting.
Carlton Morris, Derby's top scorer from last season, had a few half-chances to equalise but he could not capitalise as Lincoln defended well.
The visitors continued to have a lot of joy on the counter-attack with Derby goalkeeper Jacob Widell Zetterstrom denying House again.
John Eustace's men dominated the ball but could not find a second goal in what was a lacklustre display in their opening game of the season.
Lincoln will begin their Championship campaign with a trip to Middlesbrough next Saturday, while Derby are also on the road at Charlton Athletic.
John Eustace post-Lincoln City (EFL Cup)
Lincoln City start the new season with a win
