The Dubliner was the last man standing for Ireland at Royal St George’s after Stuart Grehan and leading qualifier Caolan Rafferty exited the competition on Thursday.
Things began well for the 21-year-old Walker Cup hopeful from the Island as he birdied the opening hole to take an early lead and went two-up on the third as Ellis bogeyed.
Both players bogeyed the fourth but the match was all square again by the turn, as Ellis produced birdies on five and eight while also matching McBride’s birdie on the seventh.
Ellis then seized the initiative on the 10th with a birdie and it was a lead he would not surrender, while his fifth and final birdie on the 12th gave him a two-hole advantage.
Both got a par on 13 and 14 before both bogeyed 15. Another bogey from Ellis on the 16th saw his lead reduced to just one hole with two to play.
McBride was certainly determined to make his opponent sweat and a par again for both on 17 set up a tense finale as the pair headed up the 18th — however, a bogey finally ended McBride’s chances.
It meant he failed to better last year’s semi-final performance but this week — where he also went further than any of his fellow Walker Cup squad members — will have done his chances of making that final 10-man Great Britain and Ireland team later this year no harm at all.
Meanwhile, Ellis went on to defeat Italian Luca Cianchetti in the semi-final and will today face Australia’s Dylan Perry in the 36-hole final.
The winner of the 122nd Amateur Championship receives an exemption into The 146th Open at Royal Birkdale, the 2018 US Open, and, by tradition, an invitation to the 2018 Masters.
The 36-hole final gets under way at Royal St George’s at 8.30am.
“It’s very exciting (opportunity to play in The Open) but someone told me last year when I was playing in this, ‘You are playing to win the Amateur Championship’, and that is what I’m playing for,” said Ellis.
“Whatever comes with that is fantastic. I know what comes with it in the back of my mind but I want to win the Amateur Championship and that will be my main aim.”
Meanwhile, major champions Sergio Garcia and Henrik Stenson will head into the weekend just a shot off the lead at the BMW International Open in Munich.
Garcia is making his first appearance in Europe since his maiden major triumph at the Masters in April while Stenson is seeking to defend the title he won by three shots in Cologne last season.
The Ryder Cup duo got to eight under in windy conditions yesterday but that was not good enough to keep pace with Frenchman Joel Stalter and Swede Joakim Lagergren, who led the way after two rounds.
Lagergren had set the target in the morning with an impressive 66 and rookie Stalter was the only one of the later starters who could catch him as he posted a 68.
Garcia had held a share of the lead at the turn after a hat-trick of birdies from the seventh, but dropped shots on the 14th and 17th stalled his momentum before he carded a closing birdie in a round of 70.
Stenson went one better with a 69 featuring birdies on the 11th, 18th, 1st, and 8th, and a single blemish on the 13th.