Renaming Columns after concatenating two Series with same Column names

I have two series namely x and y.

x:

y:

I combine these two series into a data frame as follows.

z = pd.concat([x, y], axis=1)

But in the dataframe both the column names appear as "Timestamp". I want to rename it.
When I used the below code it changes both column names at the same time.

mapping = {z.columns[0]: 'Start' }
su = z.rename(columns=mapping)

Preferred output:

How can I do this in pandas?

>Solution :

Example

x = pd.Series({0: '2022-11-16 13:00:00', 1: '2022-11-17 13:48:00'}, name='Timestamp')
y = pd.Series({0: '2022-11-16 19:13:00', 1: '2022-11-17 16:21:00'}, name='Timestamp')

Code

pd.concat([x, y], keys=['start', 'end'], axis=1)

result:

    start               end
0   2022-11-16 13:00:00 2022-11-16 19:13:00
1   2022-11-17 13:48:00 2022-11-17 16:21:00