Ferguson is tied for the lead with Frenchman Frederic Lacroix in the Challenge de España while Fyfe holds a two-shot advantage in the Cumberwell Park Championship in Wiltshire.
Helped by two eagles in three holes, Ferguson posted a blemish-free seven-under 65 in his third circuit at Iberostar Real Club de Golf Novo Sancti Petri to move into a share of top spot with Lacroix (66) on 16-under-par.
Ferguson began slowly with just one birdie on his front nine, but he burst into life on the back nine with a superb 30 which included a four-hole spell of two birdies and two eagles to charge through the field.
“The first half of my round felt a bit flat,” said the former British and Scottish Boys’ champion, who is seeking his maiden win on the Challenge Tour.
“The weather forecast made me feel a bit drowsy and it took a good part of the back nine which included two eagles to fire me up and all of a sudden the day just brightened up for me.”
The Glaswegian added: “I’ve had a third place in Cape Town and fourth in Sweden, so I have had some really good results this season. Your hot weeks will come, so it’s just about taking your chances when they do.”
A week after Conor O’Neil won on the PGA EuroPro Tour, Fyfe set up a chance to emulate the feat with a seven-under 64 to move to 13-under, two ahead of former Walker Cup player John Parry (67).
In a bogey-free effort, Fyfe birdied the third and ninth 11th, 12th, 14th, 15th and 17th also provided profitable on the inward journey.
In the amateur ranks, Scot Paul Moultrie is also chasing glory in the Scottish Senior Men’s Open at Duff House Royal.
After back-to-back 67s for a two-under total, the Royal Troon man shares the lead with England’s Stephen Jenson, who leapt into contention with a superb six-under 62.