The semi-final will take place on Tuesday. Losers Patriots, on the other hand, finished third on points table and will face Guyana Amazon Warriors in the second semi-final which takes place later that same day.
The Knight Riders wrapped up victory on Monday morning (India time) with an over to spare.
The Patriots had got off to a steady start thanks to Joshua Da Silva who was pushed up to open in the absence of the injured Devon Thomas. The wicketkeeper-batsman kept things steady after Chris Gayle was dismissed early for five.
Da Silva top-scored with 50 off 45 balls. But there was no really substantial partnership in the Patriots innings. Sherfane Rutherford and Dwayne Bravo got starts -- with 25 each -- but just as it looked as if they would launch in the death overs, they were both dismissed in the midst of a 10-ball period that saw the Patriots lose four wickets.
Patriots finished with 147/7 with Ali Khan the star for Knight Riders, claiming three wickets on his return to the starting line-up.
The Knight Riders' chase got off to a sedate start as they reached 34 for one at the end of the power-play period. The only wicket to fall in the first six overs was that of Lendl Simmons who was dismissed by a brilliant Fabian Allen catch at backward point off the bowling of Naseem Shah.
Two wickets in three balls, of Denesh Ramdin and Colin Munro, pinned the Knight Riders back. Things changed when Pollard came to the crease as he made his way to fifty from just 20 balls.
Pollard was dismissed just two balls after passing his fifty but the Knight Riders lower-order saw them to victory.
Brief scores: St Kitts and Nevis Patriots 147/7 in 20 overs (J Da Silva 50, S Rutherford 25, DJ Bravo 25, A Khan 3/19, I Udana 2/28) vs Trinbago Knight Riders Innings 150/6 in 19 overs (K Pollard 51, I Udana 25 not out, L Simmons 20, F Ahmed 2/16).