Two weekends ago, the Philadelphia 76ers wrapped up a home game against the San Antonio Spurs before embarking on a grueling six-game road trip. On paper, the entire trip looked difficult, but the Sixers got off to a solid start.

Wins over the New York Knicks, Golden State Warriors, and the Los Angeles Lakers ensured the Sixers that they would come out of the trip at least 3-3 -- and now they are headed down the road of doing so as they took on two-straight losses.

On Saturday, the 76ers visited the Los Angeles Clippers and put up a good fight in the first half. When the second half rolled around, though, Philly began to fall apart. There came a point late in the game when the Sixers put their starters on the bench as they accepted the inevitable 122-112 loss to LA.

Coming out of that game, the schedule didn't get any easier. On Tuesday night, the 76ers had a matchup against the Denver Nuggets at the Ball Arena for the first time this season. And unlike the Clippers matchup, the Sixers didn't come out strong. Instead, they looked flat from the gate and doomed themselves from the start.

“We didn’t have enough pop to us,” said Sixers forward Tobias Harris. “We didn’t have enough juice in the game, going out there and executing our stuff and being sharp offensively and defensively. We paid for it. We gave up 44 points in the first quarter and that was way too many points for our standards.”

The Nuggets shot out of this world in the first quarter on Tuesday. As a team, they knocked down 66-percent of their shots and hit on 70-percent of their three-point attempts. Not only did the 76ers allow Denver to score 44 points in the opening quarter, but they only countered that with 22 points of their own.

“They just got everything,” Sixers coach Doc Rivers said. “It was one of those games where it looked like we were running in quicksand. They attacked us early and we never really recovered from it. We got into a scrum at the end of the game, but that was what it was. They were better prepared, they were definitely more ready individually as a group, and they were better. No excuses. We just didn’t play very well.”

Tons of traveling over the past week could've certainly played a part in the Sixers' lack of energy on Tuesday night. Also, Sixers guard Ben Simmons believes the high altitude in Denver might've been a factor as well. Regardless of the driving factor of Philly's lack of energy, the dominant first quarter put on by Denver drained the Sixers' starting lineup -- and they struggled to recover.

“I think guys were a little shook and tired to start," Simmons explained. "That that also affected the communication. Guys are a little tired, but I just think in that first period, I think they shot like 70-percent from three or something like that in the first quarter. That’s tough -- especially when they got up 20 points early. It’s tough. They really punched us and we really didn't fight back until that third quarter."

Justin Grasso covers the Philadelphia 76ers for Sports Illustrated. You can follow him for live updates on Twitter: @JGrasso_ & Instagram: @JGrassoNBA.