Middlesbrough, Jan. 11: Cole Palmer missed from close range and Chelsea lost 1-0 to second-tier Middlesbrough in the first leg of their League Cup semifinal on Tuesday.

Hayden Hackney scored in the 37th minute and Middlesbrough held on at Riverside Stadium against its Premier League opponent.

Mauricio Pochettino’s expensively assembled team has been eyeing cup trophies to make up for a disappointing Premier League campaign. They’ll have work to do in the second leg at Stamford Bridge on Jan. 23.

“We had too many chances to score where we didn’t score. That is football,” Pochettino told Sky Sports. “We have another 90 minutes at Stamford Bridge, and I think we need to be positive.”

Middlesbrough hasn’t been this far in the League Cup since winning the competition in 2004.

Hackney scored after sprinting past midfielder Moises Caicedo — a big-money signing last summer — inside the box and poking Isaiah Jones’ low cross past goalkeeper Djordje Petrovic into the net.

“It was amazing. Great ball. I just got on the end of it,” the 21-year-old Hackney said. “We said before the game — try to keep it tight and catch them on the counter.”

Palmer, who shot wide earlier in the first half, just needed a tap in to equalize after Middlesbrough goalkeeper Tom Glover misplayed Enzo Fernandez’s shot in the fourth minute of first-half stoppage time.

In what should have been a simple catch, the ball instead bounced off Glover’s chest directly to Palmer, who tried to volley it in from about 5 yards out. He got under it, however, and his left-footed effort sailed over the crossbar.

The 21-year-old Palmer, who joined Chelsea from Manchester City for around $52 million in the offseason, is Chelsea’s co-leading scorer this season with eight goals.

Middlesbrough is 12th in the Championship and lost to Aston Villa 1-0 on Saturday in the FA Cup third round.

“To beat a team of the quality of Chelsea, in any circumstances for us, is unbelievable,” said Middlesbrough manager Michael Carrick, the former Manchester United star. “The lads were just exceptional. It was an incredible night.”

Liverpool hosts Fulham on Wednesday in the other League Cup semifinal first leg.

Fiorentina reach Cup semis 

Last year’s runner-up Fiorentina reached the semifinals of the Italian Cup, but it again had to do it on penalties on Tuesday.

Maxime Lopez converted the decisive spot-kick as Fiorentina beat Bologna 5-4 on penalties after the match ended goalless in Florence — although the visitors hit the woodwork three times.

After a penalty masterclass from both teams, Stefan Posch blasted Bologna’s final kick over the bar, giving Lopez the opportunity to secure Fiorentina’s place in the final four for the third straight year.

Fiorentina, which needed penalties to beat second-division Parma in the round of 16, will face either AC Milan or Atalanta in the two-legged semifinals in April. Milan hosts Atalanta on Wednesday.

Bologna is enjoying a great season and knocked out two-time defending champion Inter Milan in the previous round.

It was sitting just a point below fourth-placed Fiorentina in Serie A, with both sides fighting hard for the Champions League qualifying spots.

Bologna had the better of the chances in Florence and should have taken the lead in the 34th minute but Joshua Zirkzee’s effort came off the crossbar after some fancy footwork from the Dutch forward.

Riccardo Orsolini also hit the post for Bologna early in the second half, while Zirkzee saw another attempt palmed onto the left upright by Fiorentina goalkeeper Oliver Christensen in the third minute of extra time. (AP)