Defeats for both would see them trail by five points with only three games remaining for France and Spain while Montenegro and England would have four each to play.
For Spain it is uncharted waters to be in such a position in their qualifiers and coach Vicente Del Bosque will be looking for a much sharper performance than the one which saw them held by unfancied Finland last Friday.
However, Del Bosque's team will face a France side that looks to be a vastly improved version under Didier Deschamps from the one that produced a limp performance in a 2-0 defeat then coached by his fellow 1998 World Cup winner Laurent Blanc in last year's Euro 2012 quarter-finals.
But Del Bosque, who has now passed Laszlo Kubala's record of 68 matches at the helm, is nothing if not a reassuring presence and is not about to push the panic button just yet.
"There are still four games to go and it is still in our hands," he said. "We must not be pessimistic. We will be going to France to try and win."
Spain defender Sergio Ramos was also looking for a more memorable 101st appearance for his country than the draw with Finland in which he scored his side's goal.
"We will be facing a great team on Tuesday but we can beat them and it's that mentality we'll take there," said Ramos, who at 26 became the youngest Spaniard to reach a century of caps.
Spain will be without Jordi Alba but will be hoping that key midfield duo Xavi Hernandez and Xabi Alonso return after missing the Finnish match.
While Finland relied on putting every man behind the ball in a sterling defensive effort Deschamps - whose side beat Georgia 3-1 on Friday - will not repeat those tactics.
"The fact we are top will not change my intentions because it will certainly not alter the Spanish attitude, which is to monopolise the ball and to win the match," said Deschamps.
"It is not Friday's results that are going to modify my main line of strategy. I do not see myself preparing my team by telling them: "'Defend, defend'".
For Deschamps the one concern is striker Karim Benzema, who has failed to score for the French since June last year and was heckled by the home crowd last Friday.
England travel to Montenegro in better heart than the Spanish having demolished San Marino 8-0 while the hosts also retained their unbeaten record with a 1-0 win away over Moldova.
However, England captain Steven Gerrard - who sat out the San Marino win - has warned his team-mates not to react to what will be an intimidating atmosphere.
It cost England dearly last time they were there as volatile striker Wayne Rooney was sent off during the Euro 2012 qualifier - the match ending 2-2 - leading to him being suspended for the first two games at the finals.
"It is a massive game and we've got to make sure we take the three points to take control of this group," said Gerrard.
"You saw from the Manchester United versus Real Madrid game when Nani was sent off that it only takes one challenge, or something a ref doesn't like, and it can change the whole course of a game."
Fellow European heavyweights Germany and Italy face less taxing tussles with the Germans - five points clear of Sweden though having played a game more - hosting a Kazakhstan side they beat 3-0 away on Friday.
Italy - who lead Bulgaria by a point and also have a game in hand on the Bulgarians - travel to pointless Malta.
The Dutch have recovered from their humiliating first round exit at Euro 2012 and bid for their sixth win in six qualifiers at home to Romania, who along with Hungary - who travel to Turkey - trail them by five points.
Group A is one of the tighter groups which sees Belgium and Croatia tied on 13 points, the Belgians will host Macedonia on Tuesday while the Croats face a potentially tricky trip to Swansea to play Wales, who beat 10-man Scotland 2-1 on Friday.
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