Time is running short on MLS’s regular season, and as D.C. United presses for a playoff berth in an overcrowded Eastern Conference, every match carries increasing weight. That is especially true at Audi Field, where Hernán Losada’s team has been very good this year and will spend most of its waning days.

The first of two grand tests over five days at Audi Field came Saturday, and while United earned a point from the 0-0 draw with second-place Nashville SC, the outcome did not sit well with Losada or his squad.

“We are not happy with the point,” the first-year coach said. “I am not happy with the point, especially at home. We are always playing to win, but in the end, it’s a point and we need to take it and try to stay positive and move forward.”

It does not get any easier: On Wednesday, the New England Revolution (20-4-6), MLS’s runaway leader in the Supporters’ Shield race for most points, comes to town.

United (12-12-5) slipped one slot to sixth place in the conference, which will send seven teams to the postseason. But dropping points at home could prove costly for a team that, including Saturday’s game, will play four of its final six at home.

“Of course, we don’t want to draw, but there are still points on the table, so we’re just going to keep rolling with the punches and playing every game like it’s the final,” defender Donovan Pines said.

This result, before a season-high 18,034 spectators, extended United’s home unbeaten streak to five. But after four victories in which it scored 13 goals, D.C. was stuck in a 90-minute slog with defensively disciplined Nashville (11-3-15). It was shut out for the first time since July 31 in Cincinnati, a span of 13 matches.

Nashville, Losada said, is “a team that’s hard to break. We knew it was a matter of efficiency and, if we see our chances, you need to put those opportunities in the back of the net if you want to win against a team like Nashville.”

United did not generate many high-quality chances. Ola Kamara, who leads MLS in goals with 17, hit the post in the opening moments and was held scoreless for the fourth time in five matches.

Saturday marked the start of five games in 15 days, a stretch that concerns Losada because of personnel issues.

Since the previous game, a last-minute defeat in Orlando before the international break, Losada lost and gained players. Yordy Reyna, Edison Flores and Paul Arriola picked up injuries — the latter two while on national team duty — while Adrien Perez, Drew Skundrich and Ramón Ábila returned.

Arriola, a key to United’s flank attack, started twice for the United States but hurt a groin muscle in pregame warmups Wednesday. United is hopeful he will miss only three matches and return Oct. 27 against the New York Red Bulls.

Reyna (quadriceps) and Flores (calf) are on longer timetables.

“I can’t manage because I don’t have enough numbers,” Losada said, adding that several starters and reserves are not fully healthy. “Now the games are coming one after each other, and I don’t have enough players to rotate, so many players will have to go through fatigue and not being 100 percent recovered. It’s just about being tough and strong enough to survive.”

Perez was a welcome return after missing 15 matches with a broken foot. He started Saturday, but for fitness reasons, he played only one half. Defender Andy Najar also was limited to a half because of workload issues.

Nashville rested three players who just returned from World Cup qualifiers: Costa Rican forward Randall Leal, Canadian defender Alistair Johnston and Panamanian midfielder Anibal Godoy. U.S. center back Walker Zimmerman started.

United, seeking to avenge a 5-2 defeat in Tennessee in August, was on the prowl from the start. Aside from Kamara’s shot off the post, though, United labored to break down an organized resistance and promising buildups fizzled in the final third.

Nashville was no threat until late in the game.

United resorted to a clever set piece in the second half: Julian Gressel squared a free kick that Kamara dummied for Russell Canouse on the back side for a running blast that crashed into a defender. Canouse had two chances in the 65th minute, but former D.C. goalkeeper Joe Willis (13 shutouts) blocked his running header and stuffed his rebound bid.

In the last 10 minutes, D.C. goalkeeper Bill Hamid (seven shutouts) thwarted Hany Mukhtar’s angled drive and Mukhtar set up Daniel Ríos for a low bid that narrowly missed the far corner.

“It’s going to be close and tight until the end,” Losada said of the playoff race. “I am positive because no one believed in us at the beginning of the season.”

Notes: Midfielder Moses Nyeman and forward Yamil Asad were not in uniform. Losada did not comment on the status of Asad, a veteran who has made only two appearances since early August. … The previous attendance high this season was 17,180 on Aug. 21 against Atlanta. …

United has moved into a new training facility in Leesburg, ending a 20-year run at the RFK Stadium training grounds and other locations in and around the District. The NWSL’s Washington Spirit will eventually move into the 4,400-square-foot complex as well.