Dinamo Zagreb manager Zoran Mamic has told Reuters that he had help from West Ham duo Slaven Bilic and Nikola Jurcevic in beating Arsenal.
Dinamo sprung the surprise of the week in the Champions League, beating Arsenal 2-1 in the Croatian capital thanks to an Alex Oxlade-Chamberlain own goal and a goal from Junior Fernandes.
Theo Walcott pulled a goal back, but it was to be Dinamo's night in what was a famous victory for the club who produced the likes of Dejan Lovren, Luka Modric and Mario Mandzukic.
Now though, manager Mamic has admitted that he did have some outside help - from West Ham United manager Slaven Bilic.
Bilic and Mamic played together for the Croatian national team during the 1990's, and after Bilic guided his West Ham side to a 2-0 victory over Arsenal on the opening day of the season, Mamic decided to use the Hammers boss for some advice.
Assistant boss Nikola Jurcevic also played his part, as Mamic told Reuters after the game that the information presented by the West Ham duo was 'very useful'.
"We scouted Arsenal well and we found information given to us by Bilic and his assistant Nikola Jurcevic very useful," Mamic said. "But my players did a great job too. I knew we could stay on the same par physically with a team uncomfortable against rivals who can keep possession," he added.
Bilic appears to have Arsenal's number, and that will certainly give West Ham fans hope that he can continue to haunt Arsene Wenger during his time as Hammers boss.
The next meeting between the two sides is at Upton Park in April, where Bilic will be looking for a hat-trick of triumphs over Wenger, in what may become something of a rivalry between the two managers.