During the wrapping-up press conference following a two-day EU summit, Michel told reporters that "of course, we hope to keep in the future a very strong strategic relationship with the UK. But the EU is ready to defend and promote its interests.
"The level playing field is a very important goal and we will guarantee again the EU27 unity for the next negotiations," he noted.
Co-chairing the press conference with Michel, Ursula von der Leyen, president of the European Commission, made it clear that the EU will have three aims in talks on the future relationship with the UK: "Zero tariffs, zero quotas and zero dumping."
The EU is now ready to move to the next step of its relationship with the UK, said von der Leyen, noting that she wants this future relationship to be "as close as possible."
"The UK will become a third country but at the very end we will have an unprecedented partnership ... The time frame ahead of us is very challenging," she said.
"It's not only a trade agreement ... Many other fields are in the portfolio to be negotiated," she told reporters.
In the conclusions released after Friday's special meeting on Brexit, the EU27 leaders reiterate their "commitment to (the UK's) orderly withdrawal on the basis of the Withdrawal Agreement and call for its timely ratification and effective implementation."
They also support the Commission's decision to reappoint Michel Barnier to head the negotiations on the EU's future relationship with the UK.
Earlier in the day, European Council President Michel extended his congratulations to British Prime Minister Boris Johnson on his election victory, calling on London to vote on a proposed Brexit agreement as soon as possible.
Upon his arrival at the EU summit, Michel told reporters that "it is important to have clarity as soon as possible."
"The EU will negotiate to ensure to have a close cooperation in the future with the UK," he said, adding that "the integrity of the single market is a very important issue for us."
The two-day EU summit, the first chaired by Michel, is scheduled to focus on Brexit on Friday and the leaders are expected to issue a statement following the announcement of the UK election's results.
Johnson vowed on Tuesday to break the three-year stalemate over Brexit and end the UK's membership of the EU on Jan. 31, 2020.
For this end, he aims to present his Brexit deal to the UK Houses of Parliament before the Christmas holidays. This would mean his Brexit bill winging its way through the Westminster processes and receiving Royal Assent from Queen Elizabeth before Parliament goes into its festive season recess just a few days before Dec. 25.
Johnson's aim is to then establish a future permanent trading relationship with the EU by the end of 2020.