Vladimir Petkovic lamented his team's poor defending after Lazio's 2-1 loss at Atalanta as reports suggested the head coach had resigned.
Petkovic's men saw their winless run in all competitions extended to four with the Serie A loss at the Stadio Atleti Azzurri d'Italia on Sunday.
According to RAI Sport, Petkovic has handed in his resignation to Lazio director Igli Tare and president Claudio Lotito.
Other reports suggest he has two games to turnaround Lazio's season, with his team sitting ninth in the league with just three wins in eight.
Goals from Luca Cigarini and German Denis saw Atalanta become the latest team to deny Lazio in the league.
Petkovic said his team had been punished for sloppy defending but was pleased with their improvement in the second half.
"We paid for some ingenuous defending. We have to work (on it). We wanted to win. We believed in ourselves," Petkovic told Sky Sport Italia.
"In the first half we lacked concreteness but in the second half we started well.
"At the end, however, we paid for an avoidable error. Against these teams that close down well, you have to go forward with great speed.
"In the second half we increased the rhythm and we saw a better Lazio."
Petkovic led Lazio to the Coppa Italia crown in 2012/13 but their poor start to the campaign sees him under pressure.
Serbia coach Sinisa Mihajlovic and former Lazio boss Edy Reja, who is without a coaching position, have been linked with Petkovic's position.
|27||C. Del Grosso|
|Coach: S. Colantuono|
for S. Lucchini 57'
for G. Bonaventura 69'
for M. Moralez 83'
|Higuain rejects extension from Napoli|
|Zamora returns to Brighton|
|West Ham can cope without Valencia - Gold|
|Wickham loses on Palace debut|
|Guardiola: No problem with Matthaus and Effenberg comments|
|Cartabia excited by Deportivo loan|
|Lyon confirm Rafael deal|
|Hysaj agrees deal to follow Sarri to Napoli|
|Rafael says his goodbyes to Manchester United|
|Dos Santos ready to get going with Galaxy|
|Pochettino rejects Soldado exit talk|
|Metatarsal misery for Mulumbu|
|Benitez: Benzema and Bale going nowhere|
|Mihajlovic: Ibrahimovic would make Milan title contenders|
|Hughes not taking any risks with Bojan|
|Guardiola relishing Audi Cup test|
|Di Maria ´taking a step up´ - Silva|
|Leicester bring in defender Benalouane|
|Deulofeu doubtful for Premier League opener|
|West Ham striker Valencia out for three months|
|UEFA: Qarabag-Celtic to go ahead|
|Palace seal Wickham swoop|
|Ronaldo and Benzema to miss Audi Cup|
|Marotta: Juventus could lose Pogba|
|Kante completes Leicester switch|
|Khedira ruled out for two months|
|FA accepts Mourinho criticism of Wembley surface|
|Robben rubbishes injury talk|
|Marchisio expects Milan title challenge|
|Rafael set for Lyon move|
|Celtic ´seeking reassurances´ over Qarabag pitch|
|Wenger beating Mourinho does not affect Chelsea - Zouma|
|Rooney moved by Everton welcome|
|Mancini not worried by lack of Inter goals|
|Coloccini wants to finish career at Newcastle - McClaren|
|Ramsey: Pressure to win trophies is nothing new|
|Terry: Wembley defeat could be a ´blessing in disguise´|
|Blatter not running for IOC re-election|
|Bendtner: Wolfsburg can challenge Bayern for Bundesliga honours|
|Liverpool relishing Britannia return, says Henderson|
|Everton big enough to keep Stones - Martinez|
|MLS Review: Fire stun Dallas as goals dry up|
|New Atletico signings excite Raul Garcia|
|Cahill expects Arsenal title challenge|
|Jovetic happy with Inter debut|
|Luis Enrique: Barca defence must improve|
|Yanev calls for calm after ugly scenes in friendly|
|Coppa Italia Review: Cittadella romp to victory, Brescia rely on penalties|
|Arsenal have learned how to play against big teams - Ramsey|
|Shawcross to visit specialist over back woe|
|Fiorentina 2 Barcelona 1: Bernardeschi double sends Barca to another defeat|
|Mancini hints at Melo interest|
|Rodgers hails ´incredible´ Benteke strike|
|Galatasary 1 Inter 0: Sneijder sinks former club|
|Wenger defends Arsenal approach|
|Wembley loss has no bearing on new season - Terry|
|Porto cruise to friendly win over Stoke|
|Mourinho denies Wenger ´snub´ suggestions|
|Arsenal abandoned their philosophy to win Community Shield - Mourinho|
|Mourinho throws Community Shield medal into Wembley crowd|
|Swindon Town 1 Liverpool 2: Benteke nets stunner on debut|
|Scottish Premiership Review: Hearts win thriller on top-flight return|
|Ujah at the double as Bremen beat West Ham|
|Mourinho: We were the better team|
|Wenger hails defensive solidity|
|Rooney returns as Villarreal spoil Ferguson´s party|
|Rodriguez stunner earns Southampton draw as Caulker makes debut|
|Arsenal 1 Chelsea 0: Case of 14th time lucky for Wenger against Mourinho|
|Taechaubol announces Milan agreement|
|Jojic fires Cologne to latest victory|
|China 0 South Korea 2: Kim and Lee seal victory|
|Origi getting up to speed|
|Costa a doubt for start of season - Mourinho|
|North Korea 2 Japan 1: Halilhodzic´s men spurn lead|
|Allam brands FA ´amateurs´ as name-change row rumbles on|
|Fournier ´worried´ by Lyon pre-season|
|Swansea still working on Michu exit - Monk|
|Neuer furious at Bayern Supercup defeat|
|Wenger: Ozil signing not a mistake|
|UEFA Champions League Preview: Shakhtar ready for Fenerbahce decider|
|Lampard targets MLS play-offs for City|
|MLS Review: Goals galore as DC United win 10-goal thriller|
|Ronaldinho returns and helps Fluminense to win|
|Keane: United won´t overtake Chelsea|
|Casillas has the ´enthusiasm of a 20-year-old´ - Lopetegui|
|Blanc hopeful over Ibrahimovic knee injury|
|Guardiola laments late goal in Supercup defeat|
|Tuchel plans to keep Bender|
|Hecking happy with Wolfsburg discipline after Supercup win|
|Arsenal players too interested in selfies and six-packs - Keane|
|Confusion over Ibrahimovic´s PSG future|