Europe captain Padraig Harrington lamented a difficult start against the United States but remains upbeat, buoyed by the defending Ryder Cup champions managing to halve the final two matches on the first day.

Team Europe face an uphill battle trying to retain their crown at Whistling Straits, where hosts USA hold a commanding 6-2 advantage – the biggest opening-day lead at the Ryder Cup since 1975.

Europe struggled for answers as Team USA starred in the morning foursomes and afternoon four-balls, with four-time major champion Rory McIlroy losing both his matches and subsequently dropped for Saturday's foursomes.

While the start of Europe's defence did not go according to plan, Harrington highlighted the importance of Jon Rahm-Tyrrell Hatton and Viktor Hovland-Tommy Fleetwood halving their respective matchups against Scottie Scheffler-Bryson DeChambeau and Justin Thomas-Patrick Cantlay late in the day.

"No doubt it was a tough day," Harrington told reporters. "Clearly not what you wanted, 6-2. There's obviously still 20 points to play for. We've only just played for about 25 per cent at this stage. It isn't a good start, but there's still a lot to play for.

"My team played well today. You know, just a few times, the momentum, the odd putt didn't go in, and you need a bit of momentum. Things didn't go against us.

"But hopefully, I just think the last couple of matches there, when it was really, really tight, the boys came through, and it certainly felt like we couldn't have afforded -- those two halves at the very end were crucial for us, Tyrrell with the birdie on the last, very, very important in those situations.

"As much as we would have liked to have gotten wins on the board, we couldn't afford -- we didn't feel like we could afford to have lost those matches. Maybe a little bit of momentum swing there, and we feel good about that. And coming out tomorrow, obviously we need a big day."

Goodnight from #RyderCup Day 1.

The weekend awaits. pic.twitter.com/qlmlPUroVO
— Ryder Cup (@rydercup) September 25, 2021

Harrington added: "We just didn't hole the putts today. You know, you hole a few putts at the right time, you do create the momentum to move on.

"So it's a sort of Catch 22. Obviously the US played well and obviously they holed the right putts at the right time and fair play to them. We're certainly not second-guessing the way they played. We would like to hole a few more putts ourselves tomorrow and create a little bit more good feeling and vibes for ourselves."

"You can't just turn around and try to eat into a lead straightaway in one session," he continued. "It would be lovely if it happened, but you can't think like that. You've got to do it slowly, one step at a time.

"We've got 20 points to play for, and we've got to prepare ourselves for, hopefully for us at this stage [it is] a long battle all the way through. If we are going to get this done, it's going to be a very tight one."

American counterpart and USA skipper Steve Stricker added: "It's a great start. We are very happy with the start. But my message to the guys before I left is tomorrow is a new day. You know, let's just go out tomorrow and try to win that first session again in the morning and pretend today never happened, and let's keep our foot down and continue to play the golf that we know we can play.

"That's what we're trying to do and not try to get complacent with anything. You know, we've had some things that came up and bit us in the rear in other Ryder Cups, so these guys know that, and they are focused on tomorrow and coming out strong again tomorrow."