Niall Quinn's heroics in Ibaraki on Wednesday night, when he came off the substitutes' bench to terrorise Germany into submission, will not earn him a place in the Republic of Ireland's starting XI against Saudi Arabia on Tuesday.

The manager, Mick McCarthy, believes that the highest scorer in Irish football history is of more value late in the game against tired defences, and will therefore rely on the attacking pair he has favoured for some months: Robbie Keane, who capitalised on one of Quinn's deft headers to equalise in such dramatic fashion against the Germans, and Damien Duff, who is confirming his promise as one of the tournament's most exciting performers.

Having cited Duff months ago as a potential star of the competition, the manager is less surprised than anyone at the Blackburn man's efforts. Duff himself has enjoyed it ever since the half-time break in Ireland's opening game against Cameroon, which seemed to mark a turning point in their fortunes: trailing one-nil and wilting, they found new stature and spirit as the shadows lengthened.

"I struggled very badly in the first half along with everybody else," he said. "The sun was out and no one really got going. We struggled through that. Ever since then it's been OK and with the 8.30pm kick-off it was a lot easier, not as hot or as humid, so all the lads did a lot better."

It took some strong words from McCarthy as well as more amenable conditions, however, before the Irish produced a second-half performance in keeping with their abilities, setting them up for the German game: "I don't think anybody really got going in the first half. Mick said none of the players were winning the personal battles with the players against us. He said 'go out and if you start winning the personal battles you'll get something out of the game'. We did and it was the same again the other night."

Like everybody else in the beautifully constructed Kash-ima Stadium in Ibaraki, where Zico once plied his trade for the Antlers, Duff felt the chance of an equaliser had gone on Wednesday, by the time Quinn got his head to Steve Finnan's cross: "I thought the final whistle was about to go. We were very unlucky all night, we had a couple of good chances, including myself, so to see it go in was a shock really, but it was a brilliant feeling. Kahn is a world-class keeper, as everybody knows – it was a great finish from Robbie and Kahn was even close to saving that."

The last point is made rather ruefully. One of the Bayern golkeeper's best stops of the night was from Duff, who is aware that, playing regularly as a striker for his country now, he needs to improve a record of only one international goal in 28 matches. That came in the opening friendly of last season, at home to Croatia, when McCarthy paired him in attack with Keane for the first time.

Despite Keane grabbing most of the attention on Wednesday for his goal, Duff has been the more impressive over the two matches, build ing on the work of a fine season with Blackburn.

He is happy to award some of the credit for that to his club manager Graeme Souness: "He is always on about my performances. Halfway through the season before this he dropped me and told me for my ability I had to get more out of myself. Ever since then he's been on my back and I've just brought that out on to the international stage. I've lost a good bit of weight, but I don't want to keep harping on about that. I just think I'm a better player. I'm all the better for playing a year in the Premiership as well. I don't have a weights programme – I don't even know what the Blackburn gym looks like."

The good news for Souness is that while speculation linking his Irish star with Liverpool will not go away, the possibility of a move abroad is the one thing that has diminished for Duff during the eventful past week: "Italy or Spain? That's not for me really. I don't take to the sun too well, I've spent all the time since I got here in bed. I'll be staying in England."

And staying in the Ireland team, Quinn or no Quinn.