Germany captain Alexandra Popp hailed a "perfect day" after leading her team into the last eight of the Women's World Cup with a hard-fought 3-0 win over underdogs Nigeria on Saturday. Popp, 28, scored a 20th minute opener and celebrated her 100th cap as Germany became the first team to reach the quarterfinals. "It was a perfect day today. We put a lot of pressure on the Nigerians and the early goal gave us stability," Popp told broadcaster ZDF. "I am so happy for Poppi. It was a special game for her today, and she gave absolutely everything," added coach Martina Voss-Tecklenburg. Voss-Tecklenburg's side are yet to concede a goal in their four games at the World Cup so far. Goalkeeper Almuth Schult admitted that she had one eye on predecessor Nadine Angerer's record of seven clean sheets at a single World Cup. "Of course it would be great if I can break the record, but the most important thing is that we won. We are so happy to be in the quarter-finals." Popp gave Germany the lead on 20 minutes after Lina Magull's in-swinging corner inside the far post. The goal was allowed to stand after a video referral ruled that teammate Svenja Huth had not blocked the goalkeeper's vision from an offside position, but Popp complained after the match that the players had been left in the dark over the referral. "There were moments with VAR today where we didn't know what was happening," she said. Magull was involved again as Germany doubled the lead minutes later. The midfielder was caught on the knee as Nigerian left-back Evelyn Nwabouku attempted to clear a loose ball in the area. After reviewing the incident on the touchline, the referee awarded Germany a penalty, and striker Sara Daebritz made no mistake from 12 yards. Three yellow cards were awarded in the second half as the Nigerians were unable to battle their way back into the game on a sweltering evening in Grenoble. Schueller put paid to their hopes on 82 minutes, pouncing on a mistake from Halimat Ayinde and smashing the ball into the bottom corner. Germany will face either Sweden or Canada, who play on Monday, in the quarterfinal next weekend. The two-times champions have yet to concede a goal in four games and were almost always in control, even without key midfielder Dzsenifer Marozsan who might be back for their next game against Sweden or Canada. "Coaches are never 100% happy but that was a great performance and it's fantastic to be in the quarterfinals," Voss-Tecklenburg told a news conference. "We've played four very tough matches in very different conditions, with the heat tough today, and we've dealt with all that very well. "I'm very happy that we now have one week to relax and prepare for the quarterfinals. Part of that will be working on improving our performance in certain phases of the match, gaining more ground, becoming more confident and now allowing ourselves to get frustrated by small details." The Olympic champions have a week to prepare for next Saturday's game at Rennes's Roazhon Park, meaning Marozsan could have time to complete her recovery from a foot injury. "I might even be able to come back. It will remain painful for weeks, but I am not scared," the midfielder, the French league's best player in the last three seasons, said. "I probably cannot play an entire match but I was happy I was not needed today." There was obvious disappointment on the Nigeria side, but the African champions got a feel of the improvements they need to make to reach the top level. "It's important to play high-level teams like Germany because the players can see that even the smallest mistakes get punished," their coach Thomas Dennerby said. — Agencies