Read latest file in vi editor

In my daily routine on solaris box, i have to read the latest file in vi. For this i have to run below 2 commands:

ls -ltr
vi filename

I get the latest file name with ls -ltr command (last file in the list) and then vi to open this file.

I was sick of using 2 commands for this simple operation, so i thought of using a single command using combination of commands; following are the commands which I used for this operation:

vi `ls -ltr|tail -1|awk -F" " '{print $9}'` (includes directory listing)
vi `ls -ltr|grep -v ^d|tail -1|awk -F" " '{print $9}'` (ignores directory listing)
or
vi `ls -ltr|tail -1|cut -d":" -f2|cut -d" " -f2` (includes directory listing)
vi `ls -ltr|grep -v ^d|tail -1|cut -d":" -f2|cut -d" " -f2` (ignores directory listing)