Katie Taylor is on course to face either Russia's World Elite featherweight champion Zinaida Dobrynina or Azerbaijan's World Elite silver medallist Yana Alexyevana in the semi-finals of the European Games.
The Olympic champion recorded her seventh win over Bulgaria's Denista Eliseeva, the last woman to beat her in 2011, to move into the lightweight quarter-finals in Baku yesterday.
Dobrynina also won yesterday, as did Alexyevana, who Taylor beat in the World Elite final in Korea last year.
Dobrynina and Alexyevana meet in the last eight tomorrow, with the winner facing either Taylor or Sweden's Ida Lundblad in the semi-finals on Friday.
London 2012 Olympian Darren O'Neill, Dean Walsh, who was down in the first round against Russia's Maxim Dadashev, and Michael O'Reilly also had their hands raised in victory yesterday.
"This is effectively a European Elite Championships and we have nine into the quarter-finals. I don't think we have ever done that before," said head coach Billy Walsh.
"Fantastic performances today from all four. Dean was down, but he bit on the gum shield and went for it and won a cracking contest against a very experienced opponent."
Taylor, boxing off the back foot, took the first two rounds on her European Games debut against Eliseeva. The pick of her punches was a right/left combination in the first, and a superb combination while back-pedalling into a neutral corner in the second.
The Bray woman traded with the Bulgarian in the third, with Eliseeva finding the target with her best punch of the bout, but Taylor detonated a three-punch response.
The five-time World champion mixed it up again in the fourth en route to a 40-36 verdict across the board.
Swedish Elite champion Lundblad awaits in the last-eight on Wednesday. Yesterday's win was the 157th victory of Taylor's 164-bout career.
"It's always important to get off to a good start and I'm delighted with the win and happy to get four rounds under my belt in my first fight here," she said.
"I knew it would be a tough fight because I've boxed her so many times before. She's such a top-rank boxer, a great warrior. I knew I was going to be blowing at some stage in the fight, but it was a great performance.
"The first fight is always hard, just to get the ball rolling. You'll see in the next fight. I'll be a lot sharper.
"I think I'm more hungry now than I ever was. I want to leave a great legacy behind me and continue to win major championships."
Meanwhile, O'Neill and O'Reilly beat Raitis Sinkevics and Emir Sabotic of Latvia and Montenegro on unanimous decisions in the heavyweight and middleweight classes respectively yesterday.
"Just doing my best to hit, and not get hit. My next one is against the Slovenian," said O'Reilly, who faces Ajaz Venko in the bronze medal bout.
"He's a fighter, so I'll wait for the tactics from Billy Walsh, and see what he wants me to do."
Taylor, O'Neill, O'Reilly, Walsh, Brendan Irvine, Sean McComb, Ceire Smith, Adam Nolan and Dean Gardiner are through to the last-eight and are one win away from at least bronze in Baku.
Irvine, Smith and Gardiner will be in action today.