The brewers needed a 90th minute goal from Michael Olunga to deny the flower men a second successive win in a mid-week league match played at Nyayo Stadium
Karuturi, basking from Sunday's 3-2 drubbing of AFC Leopards', went ahead in the 48th minute through Andrew Murunga. The result left the brewers' win less in the league having drawn 0-0 with KCB in their opener.
Tusker coach Robert Matano said he was disappointed by the result and accused his players of playing cautiously.
"We should have gotten something better but my players opted to stay back a lot and it cost us. However, I am glad we have picked a point," Matano told Goal.com.
His Karuturi counterpart, Michael Nam said lack of concentration caused them three points but was nonetheless excited to have held the defending champions.
Tusker came into this tie seeking the first win of this campaign and the champions wasted no time in showing their intention.
Ugandan import Robert Omunuk raced clear with the goal in sight after two minutes, but his well taken effort missed the target by a couple of inches.
Karuturi's, first real chance of the game arrived on the quarter hour mark but Hussein Zzinda's direct free-kick from just outside the D-Area, failed to trouble Boniface Oluoch, who was making a return between the posts for the brewers, since his sending off in the opening minutes of the DSTV Cup competition three weeks back.
Both sides showed more commitment to win the game in the second half and it was Karuturi who were on hand to capitalize and take a well deserved lead.
A cross from former Gor Mahia forward John Kiplangat met Andrew Murunga in the box, who calmly converted the ball into the net for his second goal in two games, leaving Oluoch with little chance.
And as the match seemed headed for an embarrassing defeat, Olunga who had come on a couple of minutes earlier for rested Kennedy Wendo, salvaged a precious point with a well taken shot into the net, that left the visiting technical bench all but deflated.
Tusker next play a crunch Caf African Champions League tie against tournament champions Al Ahly at the same venue on Saturday.