Jose Mourinho said he was pleased Tottenham Hotspur are "still alive" in the FA Cup after the 1-1 draw against Southampton, while West Ham United crashed out in the fourth round at the hands of former manager Slaven Bilic, now in charge at West Bromwich Albion.
South Korean forward Son Heung-min opened the scoring for Spurs after 58 minutes before Sofiane Boufal levelled three minutes before time.
The result means Tottenham will be involved in another replay, after needing two matches to get past Middlesbrough in the previous round.
"They are a good team, they play at home and they react," Mourinho told the BBC. "They put some pressure on us in the last minutes. The ball didn't go out for about five minutes. They scored, but we are alive."
Southampton manager Ralph Hassenhuttl is not best pleased with the prospect of another fixture and believes his side had enough chances to win the match.
"Because the rules are not the best, we have another game, in a break in the season - I don't understand this but OK, we have to do it. It's for us not perfect but we must accept it," the Austrian said.
"We had a few chances in the second half, a clear penalty for [Danny] Ings and I don't know why that was not a penalty. I think we had so many chances it was only a matter of time when we scored."
At the London Stadium, Bilic, who was sacked by the Hammers in 2017, made eight changes as he prioritised the Championship leaders' push to return to the Premier League.
But West Brom took a shock lead when Conor Townsend drilled in his first goal for the club after nine minutes.
West Ham, struggling in the Premier League under new manager David Moyes and now without a win in four games, were given a lifeline when West Brom's Semi Ajayi was sent off in the 72nd minute, although the hosts failed to capitalised.
West Ham were jeered off by their fans, while Croatian Bilic, who also played for the east Londoners, celebrated a sweet success with his Albion players.
Newcastle United had to settle for an embarrassing 0-0 draw with third tier Oxford at St James' Park as their wretched FA Cup form haunted them again.
Steve Bruce's side are looking to make the fifth round for the first time since 2006, but they needed a replay to beat minnows Rochdale in the previous round and they will have to go the distance again after this limp display.
"Frustrating, disappointing. We didn't do enough basically," Bruce said. "Oxford, you have to say well done to them. They came and made it difficult for us but this is one of those where we didn't play well enough."
Burnley and Norwich made a combined total of 12 changes at Turf Moor, with the Canaries running out 2-1 winners.
Grant Hanley's 53rd minute goal and a 57th minute strike from Josip Drmic put Norwich in control before Erik Pieters reduced the deficit in the 74th minute.
Sheffield United won 2-0 at second tier Millwall through Muhamed Besic's 62nd minute goal and Oliver Norwood's 84th minute strike.
Kelechi Iheanacho's early goal sealed a 1-0 win for Leicester at Championship side Brentford.
Brendan Rodgers' team are chasing a trip to Wembley on two fronts and they took the next step in the FA Cup after surviving a hard-fought fourth round clash in west London.
Leicester, who have never won the FA Cup, are hoping to reach the final for the first time since 1969.
In the League Cup, they are through to the semi-finals and head to Aston Villa in the second leg on Tuesday after being held to a 1-1 draw in the first match at the King Power Stadium.
Despite Jamie Vardy's absence with a glute injury, it took Leicester just four minutes to go ahead when Nigerian striker Iheanacho met James Justin's cross with a clinical close-range finish.
