Although Clontarf played their rugby in the lower-tiered Division 1B this season, they are a much improved side to last year and Werahiko believes that this type of knockout match will be won by the team that shows the most desire and will to win.
"I don't find that the most talented team always wins these knockout games - it's the team that wants it more," he told IrishRugby.ie.
"If you put it up to a good team physically and show determination, you can put a good team off its game.
"I've been quite consistent in my coaching in that I've often got to the top four, but being consistent is not always enough to win it - it's coming out on the big days for the big moments."
Old Belvedere will certainly be determined to erase memories of their appearance in last season's semi-finals, which saw them suffer a narrow defeat to St. Mary's.
It may have been some comfort gaining revenge on St. Mary's on Saturday with a 25-19 victory, but 'Belvo were forced to battle hard for the result after a fierce comeback from the visitors who were 20 points down at one stage.
After scoring three tries from Daniel Riordan, David Mongan and Eddie Devitt before the half hour mark, a touch of complacency set into 'Belvo's play.
St. Mary's, who were also fighting for a play-off spot, took full advantage. They hit back with three tries of their own, two of which were scored by influential out-half Ian McKinley.
Commenting on the lapse in concentration, Werahiko said: "We didn't clear our lines, it might have been a bit of complacency and that put all the pressure back on us and it brought them closer going into the second half.
"Ian McKinley scored two great tries. I felt he was the reason why St. Mary's got back into the game because he was asking questions particularly around the third and fourth phase and he played a clever game."
McKinley and his men kept the pressure on Old Belvedere until the hosts' powerful number 8 Leo Auva'a completed a superb individual try, running more than half the length of the pitch and breaking through two tackles on his way to the line.
Auva'a's try was the last play of the match and ensured a bonus point victory for 'Belvo and dashed St. Mary's hopes of qualifying for the Division 1 semis.
Werahiko was quick to praise Auva'a's determination at such a late stage in the game, saying: "Leo's try was pretty special.
"There are not too many guys in the 80th minute that can run half the length of the field, knock a few guys out of the way and continue to the try-line. What can I say, that's why you need players like him."
Werahiko's men have already beaten Clontarf earlier this season in the Leinster Senior League Cup, yet 'Tarf have since built up encouraging momentum, winning ten of their 14 matches in Division 1B and finishing seven points clear at the top of the table.
"Clontarf have got a great bunch of players, they've bought in a culture and these players bring a lot of experience. It's a game we're already looking forward to," added the New Zealander.
In the other semi-final, reigning champions and table toppers Cork Constitution will host a thriving Young Munster side who have won five of their last six matches, including a hard-fought derby clash with Garryowen.
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