WASHINGTON—Davante Gardner scored 20 points, Steve Taylor scored 10 of his 14 points after halftime, and preseason Big East favorite Marquette needed overtime to win its first road conference game of the season Monday night, dominating the extra period to beat slumping Georgetown 80-72.Todd Mayo’s 3-pointer with 6.3 seconds remaining in regulation completed a comeback from a seven-point deficit in the final three minutes to tie the score, and the Golden Eagles (11-8, 3-3 Big East) scored the first seven points of overtime. Marquette then went 8 for 8 from the free-throw line to hold the lead.Markel Starks scored a career-high 28 points, and D’Vauntes Smith-Rivera had 24 for the Hoyas (11-7, 3-4), who have lost four of five and suffered a second-half collapse for the third straight game.Gardner grabbed an offensive rebound and made the putback while falling backward, and John Dawson followed with a 3-pointer to give Marquette a 72-65 lead in overtime. Georgetown went 3 for 8 from the field in the extra period.The Golden Eagles and Hoyas were picked to finish 1-2 in the relaunched Big East in the conference’s preseason coaches’ poll, and neither has come close to living up to expectations. The game ended a streak of seven consecutive Marquette-Georgetown games in which at least one team was ranked in the Top 25.The Golden Eagles’ shooting became progressively worse over its four previous games, with their field goal percentage dropping from 51.3 to 46.8 to 46.9 to 30.8. They stopped the trend against the Hoyas by shooting 44 percent.Georgetown had blown double-digit, second-half leads in back-to-back losses, prompting coach John Thompson III into major changes to his playing rotation. Seldom-used sophomore guard Stephen Domingo and role-playing senior guard John Caprio came off the bench early in the first half, giving Starks and Smith-Rivera a break from the heavy minutes they’ve been playing in recent games.The Hoyas remain without Joshua Smith, who sat out for his fifth consecutive game for academic reasons, and Jabril Trawick, who missed his fourth game with a broken jaw and isn’t expected to return for weeks.Neither team led by more than seven in a first half that included more fouls (19) than made field goals (18). In the second half, Taylor, who was a starter at the beginning of the season but has played sparingly in conference play, began teaming with Gardner to give the Golden Eagles a strong inside game.But Smith-Rivera and Starks combined for 19 straight Georgetown points during a long second-half stretch, capped by Starks’ fast-break layup that gave the Hoyas a 56-49 lead with 4:54 remaining.The Golden Eagles cut into the lead with a 3-pointer by Jake Thomas and a driving dunk by Jamil Wilson, making the score 60-58 with 2 minutes to play. The lead then alternated between two and four until Starks missed 1 of 2 free throws with 17 seconds to play, giving Mayo the chance to tie.