The Blues beat Palmeiras last night in Abu Dhabi as they lifted the FIFA Club World Cup to become the best club in the world.
Lukaku opened up the scoring for Chelsea early on with Kai Havertz scoring the crucial penalty in extra time at the 117th minute.
“It’s amazing,” said Havertz to Channel 4. “After champions of Europe, we are now champions of the world. It sounds better.
“I was nervous [taking the penalty], I have to be honest. It’s a big penalty. It’s just crazy. It was good I kept the nerves. I am very happy.
“I was the third penalty taker but I was the only one left on the pitch.
“My team-mates gave me trust. I dreamed always as a kid of this. This is an amazing feeling for me.”
Tuchel meanwhile said, “In the end if you score late you need luck to do it but we were relentless and we did not stop trying,” he said to Channel 4.
“We did not give in. We had the lead then lost it but never stopped. It was deserved but also lucky when you score late.
“The penalty does not look nervous [from Kai Havertz] but for sure he was. You cannot not be nervous in this situation. We trusted the statistics and I’m happy for him.”