rsync: how to copy files without creating duplicates?

Hello, I want to copy files from my local machine to the remote server.

The contents of a target directory on the remote look like this when issuing ls -l:

file1 file2 file3 

The contents of a source directory on my local machine look like this:

file1 file2 file3 file4 

My goal is to copy files from local machine to the remote machine so that the remote machines target directory would look like this:

file1 file2 file3 file4 

I tried to issue this command from my local machine:

rsync -r /source/directory/on/local/machine::destination-server::target/directory/on/remote/machine 

After issuing the above mentioned command, the contents of a remote machine directory look like this:

file1 file2 file3 file1 file2 file3 file4 

How could I properly copy the files so that the directory contents on the remote server look like this:

file1 file2 file3 file4 

Thank you