Alker suffered a rare blow when his caddy, Shane McInnes, withdrew from the second round of the New Zealand Open with shin splint problems.
The pair had reached the 11th green when McInnes decided he couldn't continue.
"He struggled. He actually did well to go 11 holes," Alker said after his round.
"I got concerned on nine and 10 when he was struggling up the hill."
Alker quickly found a replacement - one of the volunteer marshals following the group.
"He was just walking with us and it looked like he had big shoulders.
"I gave him a crash course: `stand here, do this, do this, do this'.
"It was kind of difficult but it was fine.
"I normally do a lot of the stuff myself so it wasn't a big deal. We got through."
Alker, one of the most personable New Zealand golfers, made sure he got the name of his new caddy - "Johnny".
The Otago Daily Times later found out the caddy-to-the rescue was Johnny Wilson, who plays off a 13 handicap at the Rangiora Golf Club.
It has been some sort of March for Alker.
He won the New Zealand PGA at Clearwater last week and is beautifully poised to add the Open this weekend.
Alker is third on 9-under-par, one shot behind co-leaders Jeff Gove and Jason Norris, after rounds of 68 and 67.
"I just stuck to my guns today, kept trooping on and tried to make as many birdies as possible.
"I'm putting great. It's just got better and better the last couple of weeks.
"I haven't done too much wrong and the big thing is that when I make a mistake, I recover.
"That's a good feeling to have."
Alker said he wasn't thinking ahead to tomorrow and the possibility of becoming the first New Zealander to win the Open since Dunedin's Mahal Pearce in 2003.
"I haven't thought about that but I think I had a pretty good plan last week.
"Mentally, I went in with a pretty good mind about it all and controlled the ball.
"I've just got to keep what I'm doing."
