Lazio manager Simone Inzaghi has admitted his players are "a little down" after surrendering a two-goal lead in a 3-2 defeat at Atalanta on Wednesday that saw the Rome club fall off the pace in the Serie A title race.
Lazio, playing their first game since February 29 after the coronavirus lockdown, went ahead after six minutes courtesy of a Marten De Roon own-goal, with Sergej Milinkovic-Savic adding a superb second from distance five minutes later.
But Robin Gosens headed fourth-placed Atalanta back into the game seven minutes before the break and Ruslan Malinovskyi riflled in the equaliser on 66 minutes.
Jose Luis Palomino then sealed the home win 10 minutes from time.
Lazio - bidding for their third Serie A title after 1974 and 2000 - have lost just three times in the league this season. Their most recent defeat before Wednesday was 1-0 at the hands of Inter Milan on September 25.
"We knew that returning against Atalanta was one of the worst opponents to have," said Inzaghi, whose side were held 3-3 by the Bergamo side in Rome in October.
"Unfortunately the title race gets more complicated and we regret this, because we're coming off a long series of unbeaten games. I don't like losing and the lads are a little down."
Atalanta are four points behind third-placed Inter Milan, who were held 3-3 at home against Sassuolo earlier Wednesday.
Eight-time reigning champions Juventus were the only one of the top three to win this week with their 2-0 victory in Bologna on Monday.
'The draw hurts us'
Romelu Lukaku struck his 25th goal of the season but Inter's title hopes stalled.
"The draw hurts us," said Inter manager Antonio Conte. "We had several chances to kill off the game. There is a lot of regret. If we look at the goals there is so much to be reviewed, small and big individual errors."
Conte's side got off to the worst possible start at the San Siro with Italian forward Francesco Caputo opening the scoring for the visitors after just four minutes.
Caputo, 32, punished some poor defending, picking up a Filip Djuricic cross to slide the ball past a stunned Samir Handanovic.
But a Jeremie Boga foul on Milan Skriniar allowed Inter to get back into the game as Lukaku stepped up on 41 minutes to score from the penalty spot.
Cristiano Biraghi then broke through following good work with Alexis Sanchez for the defender's first league goal for Inter in first-half stoppage time.
Inter could rue Roberto Gagliardini's spectacularly missed chance to give the hosts a two-goal cushion, hitting the crossbar in front of goal.
Three goals came in the final ten minutes with Domenico Berardi pulling Sassuolo level from the penalty spot on 81 minutes.
Lukaku had a goal ruled offside before Borja Valero latched onto an Antonio Candreva free-kick to tap in five minutes later.
But defender Giangiacomo Magnani bagged a point for 12th-placed Sassuolo with one minute to go.
Conte's woes were compounded by defender Skriniar being sent-off in extra time.
Roma stay fifth, six points behind Atalanta, after a hard-fought 2-1 win over relegation-threatened Sampdoria thanks to a second-half Edin Dzeko brace -- two volleys, one with his left foot and the other with his right.