Alastair Seeley equalled Robert Dunlop's all-time North West 200 record of 15 triumphs as he clinched two more wins at the Northern Ireland event.
Seeley held off Glenn Irwin and Lee Johnston to win a Supersport thriller before beating Ian Hutchinson and Bruce Anstey in the first Superbike race.
Johnston pipped Seeley in the Superstock class with Hutchinson third.
Ex-Grand Prix star Jeremy McWilliams earned a Supertwins triumph as home riders won all the week's six races.
The early part of Saturday's programme was affected by a series of red flags which included a serious crash where a female spectator had to be airlifted to the Royal Victoria Hospital in Belfast.
The spectator was said to be in a critical condition on Saturday night and county Antrim rider Stephen Thompson is also being treated at the Belfast hospital after sustaining injuries in the same crash.
Austrian competitor Horst Saiger needed hospital treatment in Coleraine for minor injuries after also being involved in the accident where Dean Harrison avoided injury despite his fall.
The opening Superstock race, which had been halted on Thursday night because of fading light, was started again only for a further red flag leading to its abandonment as organisers moved on to Supersport Race 2.
The Supersport race proved memorable as Carrickfergus riders Seeley and Irwin fought out a thrilling battle with Johnston.
All three led in the closing stages before Seeley repeated his Thursday night victory in the class as he finished ahead of Irwin with Johnston having to be content with third after failing to negotiate the penultimate corner.
The win moved Seeley to within one win of the late Dunlop's North West record and the 35-year-old then equalled the milestone after passing Hutchinson on the final lap of the opening Superbike race.
After sitting out the Supertwins event won by 51-year-old McWilliams, Seeley looked on course to set a new record of North West wins as he led during the closing stages of the Superstock event but Johnston's persistence paid off as he clinched the victory which his efforts deserved.
Johnston, 26, had led the opening Superstock race on three occasions before its eventual abandonment.
"I led the damn thing three times and if I didn't win it I would have been severely upset," said Johnston who was claiming his third North West victory after two Supertwins triumphs last year.
Seeley was still scheduled to have one final chance to set a new record but high winds led organisers to take the decision not to stage the event's blue riband North West 200 Superbike race.
The Carrickfergus man had no complaints about the decision which appeared to be the consensus view among the riders.
"I've had a good week and the wind were really getting up in that last Superstock race," said Seeley.
"To be up there on 15 wins with Robert Dunlop is a dream come true and to even have matched Joey's 13 wins here was special."
Former Grand Prix star Jeremy McWilliams said his second North West 200 victory was "right up there" as a career highlight after he pipped Farquhar by .4 of a second in the Supertwins race with Jamie Hamilton completing the podium positions.
"I never thought on the wrong side of 50, I'd be sitting on the top step of the podium at the North West 200," said a delighted McWilliams.
SATURDAY'S NORTH WEST 200 RESULTS
Supersport Race 2
1. Alastair Seeley
2. Glenn Irwin
3. Lee Johnston
4. William Dunlop
5. Keith Amor
6. Dean Harrison
Superbike Race One
1. Alastair Seeley
2. Ian Hutchinson
3. Bruce Anstey
4. Lee Johnston
5. Michael Rutter
6. John McGuinness
Supertwins Race Two
1. Jeremy McWilliams
2. Ryan Farquhar
3. Jamie Hamilton
4. Christian Elkin
5. Jamie Coward
6. Michael Russell
Superstock Race Two
1. Lee Johnston
2. Alastair Seeley
3. Ian Hutchinson
4. Michael Dunlop
5. William Dunlop
6. Martin Jessop