Despite a campaign by some to paint a picture of very friendly relations in the past between Lubavitch and Brisk - which was part of the Lubavitcher effort to convince the Modern Orthodox people at the recent Rebbe and Rav event at YU, that Lubavitch and YU are not necessarily opposing camps - a new biography of Rebbe Schneerson, by Lubavitcher R. Chaim Miller, has shown that while they may have cooperated at times, there was still significant tension between the two camps.
In the beginning of the book, on page seven, Rabbi Miller relates that the late Rebbe's father, R. Levi Yitzchak, went to R. Chaim Brisker to be tested for semicha. According to the account, R. Chaim Brisker tested him painstakingly, seeing that he was a Chasid and from the Schneerson family - trying to find a justification to deny that to him. When he didn't succeed in that, he was compelled to grant ordination. However, he lamented the fact that he (R. Levi Yitzchak) was putting his scholarly energies into Kabbalah and Hassidism.
In the endnotes to the book, the source for the story given is actually the Rebbe himself, from a talk in 1951.
Doesn't sound like R. Chaim Brisker was in love with all Lubavitchers from the story. Doesn't look like a Brisk-Lubavitch lovefest to me.