Eidur Gudjohnsen believes Manchester City's form has made Manchester United's trip to Chelsea a must-win for both teams.
Gudjohnsen will be an interested viewer when the Premier League heavyweights meet at Stamford Bridge, having spent six successful years with the Blues, winning back-to-back titles under United's current boss Jose Mourinho.
But he thinks his former club and his former manager are both fighting to keep pace with a runaway City side, who have opened up a five-point league lead after scoring 35 goals in 10 games.
Speaking at an event in Cobham with Chelsea partners Sure, he said: "It's always a special thing when Jose comes back to the Bridge and it will be two big teams with a lot of quality on display, but there's big pressure on this game.
"With Manchester City looking so strong a draw helps nobody, they don't want to lose any points on the leader.
"To stay in contention those two both have to win."
Mourinho often prefers to keep matches against elite rivals tight, a tactic which drew criticism after the goalless draw against Liverpool but paid dividends with a 1-0 victory over Tottenham.
Finishing prowess could be all-important, therefore, meaning another night in the spotlight for United's £75million signing Romelu Lukaku.
After a rampant start to the season he has gone six games without scoring, with Mourinho signalling for Daley Blind to take a penalty off him in the midweek win over Benfica.
Gudjohnsen played in a match 13 years ago where the Portuguese did the opposite - insisting the struggling Mateja Kezman take a spot-kick against Newcastle - and praised Mourinho's willingness to make a bold statement.
"I've got no idea what went on between those two...all I can say is when Mourinho makes a decision, you listen to it," he told Press Association Sport.
"Jose is one of the best managers around. His intelligence and eye for detail is what makes him one of the great ones, but also his absolute fearlessness.
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"He has a lot of respect for his players and has a touch for filling them with confidence and respect when they do their work."
Asked to choose between Lukaku and his successor in the Chelsea ranks, Alvaro Morata, Gudjohnsen added: "They're head to head, but they're completely different players.
"Lukaku is more physical, Morata has more movement in him. They are both great, but I go with my heart and say Morata."
