Resilience looms as perhaps the fundamental trait in this United States side. It endures even during the fallow periods, even when the adversity starts to pile up over the course of match. The lingering defiance eventually allowed this group to improve after a poor first half and kick off its preparations for the CONCACAF Cup against Mexico with a 2-1 victory over Peru at RFK Stadium on Friday night.

Jozy Altidore emerged as the hero on a swampy night in the District as the Americans relied on his two goals to claim victory. Daniel Chavez looped his opener off Omar Gonzalez to separate the sides after a dour first half, but Altidore led the response after the interval. The returning Toronto FC forward won a penalty and converted it at the second attempt and then tucked home the winner at the back post after 70 minutes.

The entire process proved instructive as U.S. coach Jurgen Klinsmann sifted through his options ahead of the playoff next month (live, Oct. 10, 8:30p.m. ET, FS1, FOX Sports GO). Peru enjoyed too much possession and too much space amid the first-half experimentation, but the U.S. replied by stepping higher up the field and using their energy and pace to tip the scales in their favor.

There are further strides to make in the rest of this international window as the Americans continue their preparations. There are still several improvements to make and several selection quandaries to weigh with the information gathered here. But there is at least the bedrock of a positive result to drive those efforts forward as the preparations for Mexico continue against Brazil in Foxborough, Massachusetts, on Tuesday.

Klinsmann fielded a completely revamped back four -- Michael Orozco on the right, Tim Ream on the left and John Brooks and Omar Gonzalez in the middle -- and opted for pace in the wide areas as the preparations for the playoff next month. His players accepted the responsibility placed upon them with a bright start before inevitably ceding more and more of the ball as the first half unfolded.

If Peru served as a reasonable facsimile of the challenge ahead at the Rose Bowl, then the Americans must shore up some frailties exposed as the first half unfolded. Peru offered little sharpness in the final third and struggled to get behind the American back four, but the visitors prodded Brooks and Gonzalez to jump into midfield too earnestly and tried to exploit some of the spacing issues in midfield.

Those efforts went largely for naught even as the Americans appeared vulnerable to work in combination. Peru lacked the necessary incisiveness and tempo to create gilt-edged opportunities. Their opener eventually emerged after some reluctance to close in front of the penalty area and a wicked deflection.

Little peril existed from the initial infield run from the right flank. There were enough numbers back to cope when Chavez collected on the edge of the penalty area, but Gonzalez provided too much space by initially dropping off instead of stepping toward the ball. His belated attempt to close arrived at the same time Chavez shot toward goal. His effort looped off the back of the turning Gonzalez and nestled inside the far post for a first international goal.

It took several minutes, but the Americans shook out of their funk and started to present some issues. Jermaine Jones forced a fine save from Pedro Gallese after a slicing run into the final third. Gyasi Zardes forced Gallese into a near-post save. The resulting corner allowed DeAndre Yedlin and Altidore to nod over the top for Brooks, but Brooks wrapped up the half in a nutshell by thrashing high over the bar from six yards.

Klinsmann praised the start and the end of the first half in his halftime remarks, but he rang the changes in a bid to continue his player evaluation. The influx of fresh bodies -- including Geoff Cameron at right back and Ventura Alvarado for Gonzalez in central defense -- injected some necessary energy. The home side pushed further up the field and took full advantage as the Peruvians started to tire.

Altidore engineered the lifeline out of very little on the edge of the penalty area. The returning forward -- back in the squad after missing out on a place in the squad for the CONCACAF Gold Cup knockout stage -- tempted Zambrano into the challenge as Cameron's long throw arrived and tumbled when he felt the scantest of contact. He rounded off the equalizer at the second attempt after Gallese produced a fine save to his right on the initial spot kick attempt.

Guzan protected the parity shortly after the hour when he summoned a flurry of saves inside his own goal area. His response to the initial attempt by Chavez produced the best of the saves, while his persistence at the second and third attempt allowed his defenders to retreat in time to aid his efforts.

The series of saves proved crucial moments later as Altidore handed the Americans the lead. Tidy combination play in midfield from Jones and Altidore played Yedlin behind on the right. Yedlin's initial service found its way toward Zardes on the left after a failed Peruvian clearance above the penalty spot. Zardes collected and slotted an inch-perfect ball through the static defense for Altidore to smash home at the back post.

It proved enough to carry the Americans through on the night, even as the Peruvians pushed in the late stages. The final moments highlighted the grit and the organization required to march through the next few weeks. There is need for further improvement before the big occasion, but this affair supplied a welcome boost of confidence and a series of important points to ponder ahead of the high-profile friendly ahead on Tuesday.