FA Cup holder Arsenal upstaged Liverpool 5-4 on penalties after Sunday's (AEST) 1-1 draw in the new season's curtain-raiser at Wembley.

Minamino's first Liverpool goal cancelled out Pierre-Emerick Aubameyang's 12th-minute opener in London, where a shootout was needed behind closed doors.

Japanese attacker Minamino joined Liverpool from Salzburg in January, however, he found opportunities limited as the Reds secured their first league crown in 30 years.

But after Minamino opened his account for Liverpool, Klopp said: "It was big for him and big for us because it was the only thing he lacked since he is with us.

"He didn't score a goal [before], but had situations and was close in plenty of moments. That helped of course. The shape he is in is obviously good, I think everybody could see when he came on.

"Then, the goal is more or less the logical step after performing on the level he performs now, especially in the pre-season. I am very pleased for him; it was very important for us to stay in the game and for him, just to make this first important step."

Klopp added: "He can have an impact, that's why we signed him. That's easily said. I don't want to put, after one or two really good performances in the pre-season, massive pressure on his shoulders that there's absolutely no need for.

"We have a good football team and it's difficult to come into the team anyway. But he is a player who is really useful for us, let me say it like this. It was not only the goal today. He is in between, he is really good in small spaces, his first touch is exceptional, then his decision-making between the lines is really quick. That helps as well.

"So, yes, he can be a real player for us – that was always clear. He came in in the most difficult period of all our lives, I would say, and had to adapt to different things, being alone in England in the lockdown and all that stuff. That's all not something that’s nice.

"But he dealt really well with it because he's a super professional. So I'm really pleased for him that he could score the goal today and that's another big step for him."

Meanwhile, Klopp said he is in favour of the continuation of the five substitutions rule to help with the well-being of footballers.

Five substitutions were introduced after the 2019-2020 season was suspended because of the coronavirus pandemic before resuming in June, and there are talks for the two additional changes per match to remain in 2020-2021.

"I know the discussion will then go again of whether it is an advantage for the bigger clubs. Look, I don't discuss it from that point of view, I don't want to have an advantage in the competition or whatever," Klopp, whose Liverpool opens its title defence against Leeds United on 12 September, said.

"We have 38 Premier League games in a four-week-shorter season, that says it all. All the other competitions will be pretty much the same as far as I know, so that means that these things will help. But I can imagine other teams see it differently. It is never about having an advantage; I saw it last season as well when we played in the last nine games of the season, I thought, 'Oh, good, [Manchester] City bring on five players… not bad!' But it is all about how we can get through this season and not who gets a little advantage here and there. It is really, how can we get through the season.

"I think for getting in a good way through the season, for the sake of the football players and the performance levels, I think it would make sense. But I don't make the decision."