Michel Barnier has paid tribute to Phil Hogan for his work as EU Commissioner.
The EU's chief Brexit negotiator made the comments as he gave an update on the latest in trade talks with the UK.
Speaking at an Institute of International and European Affairs event, he said he still believes a deal is possible.
Mr Barnier said the former Trade Commissioner and his team were of great value.
He said: "I will miss Phil Hogan, on whom I could always count to relay any Irish concerns to me very directly over the last four years.
"I would like to take this opportunity to thank him warmly for all the work he has done for Europe – as Commissioner for agriculture and rural development, and, more recently, as Commissioner for trade.
"In particular in the context of the current negotiations with the UK, where he and his team of trade experts, including Sabine Weyand, have been of great value."
Mr Barnier added that he used to meet Mr Hogan weekly while he was Trade Commissioner that he looks forward "to working with the future Commissioner of Irish nationality in the final stretch of the negotiations with the UK".
Brexit
He said that we are now less than four months away from January 1st, 2021 when the UK is set to leave the EU and added that the coronavirus pandemic "does not stop the Brexit clock from ticking".
Mr Barnier said: "This is the date chosen by the UK itself for its 'economic and commercial Brexit', after the 'political Brexit' in January this year.
"Because, as you know, the UK refused any extension of the transition period. We have no more time to lose.
"We must have a final agreement by the end of October if we are to have a new partnership in place by 1 January 2021."
He said that the "sense of urgency" to complete the tasks associated with Brexit "is strong" in Ireland and Northern Ireland.
He added: "Without a doubt, Ireland is the Member State most affected by Brexit.
"And of course, for the island of Ireland, Brexit negotiations have not just been about trade and the economy. But, more existentially, about maintaining peace and stability.
Mr Barnier said: "I have exchanged views with the Dáil and Seanad, as well as all the Irish Members of the European Parliament.
"Together, we carried forward the close relationship between Ireland and the rest of the EU, based on solidarity and respect."
He added that he was "particularly worried - and disappointed - by the UK's lack of engagement" on a number of issues to date, and that "we will not sacrifice - never sacrifice - the EU's long-term economic and political interests for the sole benefit of the UK".
