Wayne Rooney leads D.C. United in the 2019 MLS season. (Express illustration/Washington Post and Getty Images)

D.C. United caught lightning in a bottle in the second half of the 2018 season, as the confluence of Audi Field’s opening and Wayne Rooney’s arrival led to the most electrifying four months in franchise history. So what can United do for an encore? Four months after that run ended with an opening-round playoff exit, the club begins the 2019 campaign with a home match against reigning MLS Cup champion Atlanta United (6 p.m. Sunday on ESPN). Here are five storylines to watch as Rooney and Co. kick off the new season.

Rooney tackles his first full MLS season

The former Manchester United captain became the biggest name in D.C. United history upon joining the club last summer, and his production lived up to that billing: Rooney racked up 12 goals and seven assists in 20 games, earning a spot on the MLS MVP shortlist. This year, Rooney has had the benefit for a full preseason to further develop a rapport with his D.C. teammates. But the 33-year-old forward will have to endure the rigors of a full, 34-game season this time around, and deal with a harsher travel schedule (United played the bulk of its road games before Rooney’s arrival last season). His durability certainly looms large.

Acosta prepares for the next step

No player benefited more from Rooney’s arrival than midfielder Luciano Acosta, who posted 10 goals and 17 assists in his third MLS season — both career highs. He then found himself on the verge of a big-money move to European giant Paris Saint-Germain, but the transfer fell through at the last moment. Entering a contract year, Acosta appeared to move past that disappointment and refocus with some strong performances in the preseason. If he delivers another productive season, the 24-year-old could position himself for an even more lucrative move than the one he would have made to PSG.

Can Rodriguez fill the Asad vacancy?

While Rooney and Acosta grabbed most of the headlines last season, winger Yamil Asad was quietly lethal (nine goals and eight assists) as a complementary attacking option. But after enjoying his services on loan last season, United failed to reach agreement with Asad’s parent club, Argentine side Velez, for a permanent move. Filling the void left by Asad on the left flank will likely be another young Argentine: offseason signee Lucas Rodriguez, 21. The promising midfielder, who represented Argentina at the 2017 Under-20 World Cup, will be expected to produce immediate results.

Defensive options pose questions

United filled its biggest hole this offseason with the signing of right back Leonardo Jara from Argentine power Boca Juniors. But the club didn’t add a veteran in central defense, where 33-year-old Frederic Brillant remains the starter alongside stalwart Steve Birnbaum. United coach Ben Olsen said last season that he might have overused Brillant — who lost his starting job to the since-departed Kofi Opare for a 10-game stretch — and the lack of depth behind the veteran could be a concern in 2019. But rookie Donovan Pines, a homegrown signing out of Maryland, is an enticing prospect at the position.

D.C. makes itself at home at Audi Field

United finished fourth in the Eastern Conference last season with a 14-11-9 record, including a 12-2-1 mark at Audi Field. After mostly playing to sellout or near-capacity crowds at the 20,000-seat venue, United will want to ensure that its home form and reinvigorated fan base are sustainable — and not just an aberration brought on by the buzz of the Rooney signing and the stadium opening. A more measured schedule should help: After risking fan fatigue by packing 15 matches at Audi Field into a 14-week stretch last year, United this season has a normally balanced schedule — 17 home games from March to October.