Inter were three goals up in the 28th minute as Lukaku bagged his second after Roberto Gagliardini had smashed in a volley.
He played in Benfica's 2-0 win over Moreinense on Saturday after which Benfica coach Jorge Jesus commented he was "pretty sure" it would be his last game for the Lisbon-based outfit. Enditem
Schalke has worn out 23 coaches in the last 20 years.
"In fact, we're still waiting for legal guidelines to run the games," Dortmund's sports director Michael Zorc complained.
Newly-crowned US Open champion Dominic Thiem extended his winning streak to nine matches as the 2018 and 2019 Roland Garros finalist saw off American qualifier Jack Sock 6-1, 6-3, 7-6 (6) in two hours and 22 minutes.
Both are very much underdogs against Manchester United, Paris Saint-Germain and Istanbul Basaksehir (Leipzig) and Real Madrid, Inter Milan, and Shakhtar Donetsk (Gladbach).
After the restart, both sides traded attacks as Dabbur pulled over the target from a promising position before Joshua Zirkzee rattled the woodwork from a tight angle on the hour mark.
The Israeli Euroleague side added that the contract is for three months with an option to extend until the end of the current season.
In Sunday's other fixtures, Sassuolo enjoyed a 4-1 victory over newly-promoted Spezia, while Hellas Verona edged past Udinese 1-0. Enditem
With the score tied at 68-all before the final quarter, Sichuan took charge of the last 10 minutes despite Shao's departure.
There was a hint that the ball could have brushed Jota's arm, but the goal was allowed to stand and Liverpool now have three wins from their first three games of the season.