Jesus did believe in ONENESS of G-d:
Matthew 22:37-38
…
37And He said to him, "'YOU SHALL LOVE THE LORD YOUR GOD WITH ALL YOUR HEART, AND WITH ALL YOUR SOUL, AND WITH ALL YOUR MIND.'
38"This is the great and foremost commandment.
http://biblehub.com/matthew/22-38.htm
And here Jesus repeated concept of G-d held by Moses (and repeated several times in Jewish Scripture):
6 And the Lord, your God, will circumcise your heart and the heart of your offspring, [so that you may] love the Lord your God with all your heart and with all your soul, for the sake of your life.
http://www.chabad.org/library/bible_cdo/aid/9994
And Jesus mission was to enforce it as a follower of Moses.
Regards