Famara Diedhiou doubled the lead with a 44th-minute penalty after a foul on Jack Hunt and Andreas Weimann netted the third with a near-post finish after 66 minutes.

Johnson joked: "My streaks are getting shorter – only four games this time! Now we can hopefully start another more positive one.

"The early goal helped settle us and I felt we paid Luton total respect with our performance, which was strong in all departments.

"I'm particularly pleased for Marley Watkins, who suffered when I tried to change the dynamic of the team and has not played as many games as he might have.

"Today he showed his strengths and gave us something different on the right flank. We had to stop conceding goals and played with one brain as a team."

Johnson's one regret was Diedhiou's hashed goal celebration, designed to mark his son's birthday, after the striker raced to the bench, tried to don a paper hat that didn't fit and then failed to pull a party popper.

"It was a disaster all round and I ended up with tinsel all over my dug-out," said Johnson. "I never knew it was coming and what concerned me was that it might look disrespectful to Luton. So I used it at half-time to drive home that the game was certainly not over."

There was no cause for celebration for Luton, whose losing run away from home in the Championship stretched to eight games.

Boss Graeme Jones said: "The players had put a lot into the Fulham game and today they had nothing left. The senior ones just about coped but it was very hard on our younger lads.

"We talked so much about City's crossing ability and trying to make sure we had an extra man in the box but got caught out really early in the game.

"I could see we were not coping at the back so changed the shape, which worked OK without us ever having a spark in the final third of the pitch.

"I didn't get a clear view of the penalty so cannot comment on it but we gave ourselves a mountain to climb by conceding early and didn't have the energy to recover.

"There were a few home truths delivered at half-time and at the end we had a really honest discussion in the dressing room. The lads are a good bunch and will come again."